Get too bored will all the classes I play so I switch a lot but I'll give details about the classes!
Operative/Scoundrel - Assist DPS. Not good when you don't have anyone good to do this assist part with
Juggernaut/Guardian - By far my favorite class. Best class for wzs imo because you get a 4 second immunity to CC on charge, taunts and a friendly charge that counts as a taunt, aoe slows and with amazing amount of consistent DPS. Only seen Aznpower, Sion along with myself, run this spec amazingly as a DPS.
Sentinel/Marauder- I was trying to think why the heck I was even playing this class when I remembered a forum stating that no one would be able to beat me 1v1 and yeah sadly that was the only reason I made it. Fun and joy is over though. Still haven't been beaten 1v1 by any sents/rauders on it since its got out of recruit and now that I proved my point I have no use for it. I can do everything with this class that I could do on my guardian/jug. Only thing a sentinel has on a jug/guard is support abilities which imo doesn't compare to the taunting/control/protection abilities of a guardian/jug.
Gs/Sniper- Awesome burst ability. If played well can be very mobile. Only thing is 99% of them dont play mobile. So far the only one Ive seen do this well is Varlan. Amazing slinger and will be scary as hell when fully geared.
Sorce/Sage - Loved playing madness on this thing. If dmg was bolstered a little more on top of less force usage needed in this spec, I wouldn't mind going back to it. Lightning spec required you to stand still too much.
Powertech - By god! By far my favorite pre-50 toon I've ever played. just rofl all over pre-50s and I might just make a vanguard to have the luls again. Gave it up due to being a glass/cannon and not having enough abilities too hit. I'm too ADD not to have 500 skills i can roll my fingers over.