So, I really like fielding Ardus as a unit for his Host of Crows ability; archers with Wind Rune and Combat Ingenuity are fantastic , laying on tons of blight and staying out of combat really well. Host of Crows lets you take them at 2 trays for 30 points instead of 4 trays at 44 points, and if you're taking three of these units, the savings more than pays for Ardus himself.
Ardus is, in theory, more valuable than adding an extra rank to each of these archer units. My main issue now is how best to use him, and which upgrades suit these uses. He's obviously really strong in melee. As a single tray, he can get a flank charge pretty easily (if he hits a corner, he can always choose which side to square up against; see 77.2). In the builds I've been playing with, there's almost always archers around (like I said, I'm taking 3 units of them) so he can deal blight with his surges. If Combat Ingenuity allows him to take the one-surge version of the archers' ability (which is how we've been playing until an FAQ arrives) he can deal a crippling amount of blight fairly easily. If there's a Lancer nearby as well, he could also possibly assassinate unit upgrades and/or take down high armor units more easily.
So let's look at his upgrades:
Unique - These are both so good and so cheap that you should almost always take one:
Ancient Technique - Getting a both-dice full reroll for only 2 points seems like a no-brainer. This is what I've usually been taking.
Ardus' Fury - Giving this one more thought. Again, assuming the ruling is that he can steal the one-surge version of the archers' surge ability, this would allow him to guarantee one blight on almost every hit and two blight when he's willing to dial in Surge instead of the other appealing options on his modifier dial. With a Lancer nearby it becomes even better, piling on mortal strikes.
Artifact - Lots of options, but much more expensive to get anything good:
Fortuna's Dice - Less dependence on luck is always great, and with a white rally option on his modifier dial, you can use it every turn if you want.
Reaping Blade - There's only one blank face on the white dice, so you'll definitely play games where this doesn't do anything. Still, when it does happen, you'll usually be glad it did? This is also the cheapest option.
Shield of Margath - Seems really strong, especially since Ardus' melee happens on initiative 3 and has a white +1 Defense modifier.
The Duskblade - Feels overcosted on Ardus, both in points and in how many surges it takes to activate. Wouldn't you usually rather spend those surges on blight?
So what does everyone else think? It seems like he's got a lot of potential and good flexibility, but deciding which options to take ahead of time in a take-all-comers list is tricky.