I would recommend using Combustible if you have Bursting Flame spec'ed. You use Flame Burst a lot and the additional damage is great.

The problem is that you're only looking at it from a PvP perspective. Based from what I can tell, the OP is talking about PvE.

I leveled as Pyrotech up to 40 and then went AP the rest of the way and I have to say that I do enjoy playing as AP a lot. Now that I'm 50 and have some gear, I find that AP does damage more consistently and Pyrotech does more burst damage. Pyrotech relies pretty heavily on having Rail Shot procs and there are just times when you're just unlucky and can't get the procs whereas AP still continues to deal the same amount of damage, proc or not. As a disclaimer, I don't want to give you misinformation, it's just from my personal experiences and the personal numbers that I see in PvE. I don't see any huge difference in numbers for the most part but you do have to stay relatively close in melee as AP. I raided as an assassin so I'm used to the melee range, in fact, because Powertechs have Flame Burst, it's actually significantly easier on me now that I've an additional 6m, although Rocket Punch and Retractable Blade is still 4m but it's not as bad.

Advanced Prototype seems to do just fine from my experience. I tried out Pyrotech to see what the damage comparison is and although Pyrotech can be really bursty, the damage is also very inconsistent. Pyrotech requires Rail Shot to proc and if it doesn't, then it just doesn't deal enough damage. Advanced Prototype however, seems to be able to deal consistent damage as well as really good AoE from Flamethrower (great for flashpoints). I plan to continue using it as I find Pyrotech to be a tad too unpredictable (in both heat and damage).

Because it is not a PvP-only game?

Generally speaking, if you're taking endurance over aim, you're probably going to be a tank. However, with that said, most mods retain the same total number when you add both aim and endurance together, so you're really just trading some aim for some endurance. If PvP is what you're focused on, I would go with the endurance since being melee generally means you'll be taking more damage (not to mention you need the health to close in on the pesky ranged).

Ah, okay, I just wanted to make sure since a lot of our gear actually gave us accuracy. I was mostly more concerned about lowering the target's resistance to tech attacks than Rail Shot missing.

How useful is accuracy for powertechs? I know that most of our attacks are tech therefore it cannot miss, but accuracy says it also reduces the target's resistance. So is stacking accuracy a good idea? And if so, how much is a good number?

People tend to keep referring to Pyrotech DPS but how about Advanced Prototype? Is the damage difference that big that no one bothers with it?

Have you spec'ed Advanced Prototype and if so, how were the results in comparison?

Understandably, I know that there is not definitive answer on who is dealing more damage on our end. However, what I want to know is the damage significantly lower than say an assassin or merc or whatever else because that is easier to tell. I appreciate the replies.

I was wondering how well a powertech can DPS. I currently play an assassin but I find a powertech to be a bit more enjoyable to play but not sure if the DPS is viable in end-game raiding. Also, how is the DPS comparison between Pyrotech and Advanced Prototype? I was thinking of trying Advanced Prototype for raiding since I love the concept of using a flamethrower but not sure how it'll work out.

The problem isn't so much with having to keep it up all the time, it's having to constantly watch it. Without a UI that we can customize, we're constantly looking at the bottom of the screen, either that or keep mashing the Dark Ward button. I personally don't like the way the UI is currently as it doesn't lend itself to that sort of play. On top of that, there are no macros to help assist that problem. So I agree with the OP, it definitely is a hassle playing an assassin tank (not sure about jugs or powertechs).

I agree, but it doesn't only apply to assassins. Many other classes have stacks and procs to watch for as well.

I played a sorc during beta and didn't really enjoy playing one. I also liked the idea of using a saberstaff and it just so happens assassins are pseudo-casters along with talent trees that allowed flexibility. I never played a melee/stealther in my previous MMO experiences so I figured I would try one out.