The kinetic fields would only protect against stubbers, bolts and other solid projectiles. The ME universe completely lacks energy weapons which is probably the point where it and 40K are most incompatible. So las and plasma weapons would just ignore the "shields" of an ME guy. On the other hand ME ubiquitously applies anti-grav tech to literally everything down to the most mundane **** whereas in 40k anti-grav is one of the most misunderstood artifacts of the dark age of technology frequently produced in small quantities for limited applications but totally mythical in it's function.

With 40k vs ME you're talking about rules that are so divergent they don't allow for each other, it's like the old Star Wars vs Star Trek arguments but even dumber.

Well, Geth use plasma weaponry, and it gets stopped by kinetic barriers just fine - probably because plasma is "physical" as well, and the barrier does not discriminate between molecules in the form of a solid projectile or a cloud of gas, being interested only in the speed they impact the shield.

Lasers are more tricky - barriers do not protect against radiation, which leads me to believe that the only thing possibly stopping a las blast would be the armour, whose properties we know very little about.

All in all, the last segment of your post sums it up nicely. Debates such as these are useless simply because there is very little true common ground between the two settings. It's already nigh-impossible to relate these universes to our real world because they use fictional materials with made-up properties instead of hard contemporary science - removing the modern reality from the equation and letting fictional rules compete with fictional rules is a recipe for disaster, and the only thing that can result from it is a shouting match between opposing personal opinions and interpretations.

Hell, 40k does not even have a real canon as far as these details are concerned, and - thanks to generous artistic license - does not know itself what kind of damage weapon X can actually do to target Y. Under these premises, how can we possibly compare it to something else .. when we don't even know what "it" actually is?

Incendiary rounds, warp rounds, cryo rounds... these sound like energy weapons to me, or at least within tolerances. Also, Collector Particle Beam?

Incendiary rounds are just bullets that burn, cryo rounds are just bullets made of cold stuff, warp rounds are bullets imbured with crazy gravitational properties by a biotic. Reaper/Collecto/Thanatos Cannons are all the same technology in that they magnetically fire a tight stream of molten iron at a small fraction of the speed of light which just makes them the next logical step after all the railguns everyone was already using in the setting.

Lasers are more tricky - barriers do not protect against radiation, which leads me to believe that the only thing possibly stopping a las blast would be the armour, whose properties we know very little about.

It's been awhile but if I recall ME universe armor is usually a multi-layered composite with an ablative surface designed primarily to try to deflect and/or shatter the tiny pieces of very high velocity magnetic alloys that their rail/gauss based small arms tech shoots. Which might help explain why by ME3 half of everybody just gave up on guns and started trying to kill each other with monoswords. Either that or it was just derpy take your pick, personally I think ME3 in particular started departing from the series previously fairly hard-scifi roots long before the robot ghost child appeared and flat out ruined the entire series. Half the new weapons they introduced felt like they belonged more in Ratchet and Clank.

We had a lot of discussion about WH40k-universe vs. ME-universe. But what if we decrease the scale?

What would happen if, for example, ordinary rogue trader appears with his ships on the orbit of Eden Prime? And when I say "ordinary", it means no giant flotillas of a pair of battlecruisers, dozen of cruisers and tens of frigates. Just something like a light cruiser and one or two escort frigates.

I've actually thought a fair bit about using Mass Effect as the basis for a minor Xeno empire for my Rogue Trader to run into. Of course, the idea there is not to port-over the entirety of Mass Effect, but rather to use it to create some kind of "odd" technological society that has some kind of internal consistency, while putting everything solidly into the 40k universe's basic nature.

If this particular xeno mastered gravic/mass alteration technology early, say by retroegeneering a necron thingy on their world, and applied it to everything, they might have micro-railguns as assault rifles, or use ships that kinda look like the Alliances (but on the appropriate scale). Maybe they're psychers (biotics) focus exclusively on a related kind of telekinesis to keep from falling to chaos. (kinda like an eldar path)

I've actually thought a fair bit about using Mass Effect as the basis for a minor Xeno empire for my Rogue Trader to run into. Of course, the idea there is not to port-over the entirety of Mass Effect, but rather to use it to create some kind of "odd" technological society that has some kind of internal consistency, while putting everything solidly into the 40k universe's basic nature.

If this particular xeno mastered gravic/mass alteration technology early, say by retroegeneering a necron thingy on their world, and applied it to everything, they might have micro-railguns as assault rifles, or use ships that kinda look like the Alliances (but on the appropriate scale). Maybe they're psychers (biotics) focus exclusively on a related kind of telekinesis to keep from falling to chaos. (kinda like an eldar path)

If it means anything, I once created 40K Asari for a RT game. Saying they have ME-style tech is as easy as saying that if they were left alone for their development, and had no bizarre Yu'Vath artifacts lying around, they could easily develop along that path on their own, perhaps an abundance of the correct BS resources were in their system and they thought "well this stuff is cool, let's use that." And yes, the Asari had lovely 40k tendencies like "We're all Psykers, so our society has strict rules regarding that kinda thing." and "We don't trust you and we would rather you just f**ked off somewhere other than here, but we're Asari, so we'll be polite." and "OH GODDESS ORKS WHY???"

I've actually thought a fair bit about using Mass Effect as the basis for a minor Xeno empire for my Rogue Trader to run into. Of course, the idea there is not to port-over the entirety of Mass Effect, but rather to use it to create some kind of "odd" technological society that has some kind of internal consistency, while putting everything solidly into the 40k universe's basic nature.

If this particular xeno mastered gravic/mass alteration technology early, say by retroegeneering a necron thingy on their world, and applied it to everything, they might have micro-railguns as assault rifles, or use ships that kinda look like the Alliances (but on the appropriate scale). Maybe they're psychers (biotics) focus exclusively on a related kind of telekinesis to keep from falling to chaos. (kinda like an eldar path)

If it means anything, I once created 40K Asari for a RT game. Saying they have ME-style tech is as easy as saying that if they were left alone for their development, and had no bizarre Yu'Vath artifacts lying around, they could easily develop along that path on their own, perhaps an abundance of the correct BS resources were in their system and they thought "well this stuff is cool, let's use that." And yes, the Asari had lovely 40k tendencies like "We're all Psykers, so our society has strict rules regarding that kinda thing." and "We don't trust you and we would rather you just f**ked off somewhere other than here, but we're Asari, so we'll be polite." and "OH GODDESS ORKS WHY???"

Superman kicks Batman's ass every time.

The Eldar don't fall to Chaos because they only follow one discipline, in fact they have a wide range of powers that are frighteningly devastating. They don't fall to Chaos because they are super on guard all of the time since they are so highly psychic they feel their souls being devoured if they're not cautious, and they can also sense that in their neighbours so they can kill them if they start to fall.

That's really the difference between Mass Effect and 40K. In 40K, magic is effectively real, as are the Gods. The Gods have tangible, real presences inside the 40K universe and no matter how safe you are, if they notice you they can come after you.