I've been thinking about these to guys recently, which is tough for me, because I haven't really flown either one of them any significant amount. I wanted to at least theorize a bit about, however, about how and when you might use one vs the other. They share a number of similarities that makes this an interesting comparison: In their basic forms, they're both close to 30 points, and they each have a number of really excellent upgrades that can push them into the mid-30's. The more loaded form is the one I'd like to compare, because they're more directly related. The question I'd like to explore in more depth is in what situation do you take one vs the other? "Take both" is a reasonable answer, but this question is assuming you're only taking one. I think a lot of this is stuff people already know, but I'm just laying it all out here to be as thorough as possible for myself.
Soontir Fel 27
Royal Guard Interceptor title 0
PTL 3
Autothrusters 2
Shield Upgrade 4
36 total squad points
vs
Darth Vader 29
TIE/x1 tite 0
Advanced Targeting Computer 1
Engine Upgrade 4
35 total squad points
First off, there's some flexibility here. Fel can change his second modification to Stealth Device or Hull Upgrade to save a point and change his defense profile. Vader still has an EPT and, if you wish, a Missile slot to fill. There's a number of comparisons that are independent of these things, however. I'll start there:
Piloting Skill: PS9 is PS9. It's a magic number in this game. Vader can use his EPT to get ahead here.
Actions: Both have 2 actions, and rely on their two actions, so blocking them can be very bad. They have the same set of actions available in their bar, with the exception of Target Lock with Vader. Fel effectively gets a free Focus from the stress of his every-turn usage of PTL.
Movement: In raw dial options, the Interceptor has better K-turns (if you'd ever use them) and the great 1-turn. The Advanced has the useful 1-bank. The 1-bank isn't as useful as the 1-turn overall, but is pretty good. In the above formats, both have Boost and Barrel Roll options. In terms of practical dial options, Baron Fel's is somewhat more limited because of the need to pull green maneuvers to clear stress. Consequently, Fel can pull more maneuvers in a pinch, but Vader is probably less predictable overall. Fel can also usually spare more actions for post-movement re-positioning because of his free Focus token.
Offense: The Interceptor has 3 red dice, and they will frequently be modified by a Focus token. Getting 4 dice at close range is usually not difficult with Baron Fel's numerous movement actions. The Advanced has 2 red dice, but ATC effectively gives another, always-critical-hit red die if a Target Lock is present. This makes for some complex comparison between the two.
-If targets are switching every turn or so, because they're either being destroyed or the pilots are in a knife-fight and a different target presents itself each turn, the high native attack of the Interceptor is substantially better. It doesn't require the additional Target Lock action to activate. In such a situation, Soontir Fel finds himself with an effective three actions vs Vader's one, if Vader hopes to keep his offense up. Soontir Fel with a Focus has an expected number of hits of 2.25/3 (range 2-3/range 1), while Vader has an expected number of hits of 2/2.5 if no Focus token is spent, and 2.5/3.5 if Focus is spent to boost the attack. Vader always guarantees a crit result as well.
-If a single main target is focused on over several turns, such as a ship with large hit points or a high defense small ship, the Action cost for ATC becomes less significant. This makes Vader more freely able to use an action to boost his Attack, substantially pushing it ahead of Soontir.
-Additional upgrades allow Vader to substantially increase his offense. The excellent Predator EPT is a common example, and increases his output in both switching and focused target situations. Furthermore, a Missile upgrade can add some options. A Proton Rocket can be fire by Vader and almost guarantee 5 hits at range 1. An Ion Pulse Missile can significantly reduce movement options of your opponent, and a Concussion Missile is a nearly guaranteed 4 hits in the opening engagement. Ordnance is generally not worth the points in this game, but if it's worth it on anyone, Darth Vader is that anyone. His high PS and dual actions make it extremely reliable.
Defense: Both the Interceptor and TIE Advanced have 3 green dice. The Advanced has an extra shield in this format, but lacks Autothrusters. In the absence of Turrets, Autothrusters are useful only against range 3 shots (still quite useful). In general, the range 3 utility is most important against high Attack weapons like HLCs, as 3 AGI dice plus the range bonus plus multiple actions can defend pretty well against most primary attacks. Even then, Autothrusters allow a degree of predictable defense that I think is better than the extra shield of the Advanced. If turrets are involved, it's not even close. When you combine this with the extra effective action of Soontir Fel, his defense is notably stronger than Vaders. Vader can use his EPT to even this disparity out somewhat in the form of Lone Wolf, assuming the triggering factors can be satisfied. If a Focus is available, Lone Wolf will be 5/8ths as good as Autothrusters once, or 3/8ths without Focus. Lone Wolf can also be used against many attacks that won't trigger Autothrusters.
Taking all of the above into consideration, I'll now run down some major threats and see how these two Aces stack up. Generally speaking, neither are bad against these threats, but one will be better than the other.
Phantoms: Both PS9, Vader can be made to hunt Phantoms at PS11. They'll cause problems to a Phantom, depending on initiative.
Fat Turrets: Soontir Fel has autothrusters and so is much more durable. Vader can use ATC to start doing significant critical damage to them early, and still won't be easy to kill, particularly with Lone Wolf.
TIE Swarms: Vader is a bit less predictable to block, but Fel has better offense against fleeting targets. The are approximately the same durability against TIE Swarms, who are pretty bad at long range fire where Autothrusters are keying in.
4-5 ship Rebel/Scum List: Blocking is less of an issue than with TIE swarms and they are more powerful at long range, improving Soontir's movement and defensive positions compared to Vader. They're also tougher, suggesting the ATC advantage would improve, but I think there will still be a lot of shifting targets so Vader's action economy will be hurt.
Automatic Damage: I don't know if this will really be a thing, but Vader's extra shield is important here.
Firesprays/Aggressors/Shuttles/Elite Fighters: Tough targets with firing arcs play to Vader's strengths without activating Soontir's defensive strengths.
Did I miss anything? If you've managed to make it this far, thanks for reading. I'd appreciate any comments and criticisms.