I'm a bit curious if anyone's been having difficulty using some abilities. What I mean to say is when you click on abilities when they say they're ready; are you actually having them going off consistently? For the most part I seem to do well but on occasion it seems some of my abilities seem very reliant on the animation before you can move on to do the next attack even if you have an ability off GCD, in effect not taking full advantage of an open time frame. It seems to happen to me a lot with things such as retaliate, disruption, ravage, Unleash & on occasion my force grip seems to glitch out too. For example sometimes when I click on my force grip it wont actually apply its effect as if it missed however my character will continue to follow the animation of channeling it for the next 3 seconds and not permit me to use any attacks until it's done without ever having applied any damage. Also as noted Ravage does well for the most part but it seems when it does happen that no matter how much I try to activate it that it will just get caught in an unending chain of doing the animation (again full animation without letting me do anything while it does it) without actually dealing damage or activating its CD time. I haven't had these kind of issues with any other class so I just wanted to see if anyone else has experienced issues of this kind as this is usually how I end up dying and certainly does not make it enjoyable to be unable to do what you know it should be doing.

Personally at this point until you're level capped I haven't exactly seen much point to trying to use power over crit or crit over power. For the most part you should just take whatever has an upgrade on the str on it regardless of that kind of stat which you should see a lot of. Only reason I dont take str over anything is if it would be a drastic loss of another stat. For example I think at one point I had the possiblity of taking an item that had 2 more str, 40 more armor and 1 more crit but id lose 14 endurance so in that case I passed because that was a very minor boost to damage at the loss of a lot of health. In theory though later on down the line I'm thinking power will probably play a bigger role than crit and surge maybe even more important than that but that's just a theory. You'll have other stats to worry about down the line too like alacrity but accuracy should always be taken if possible. I've found it hard to find any accuracy gear while leveling so when I do see it if I don't lose to much of other stats I am going to be taking it.

Atm I am fully in the rage tree though there is 1 alteration I have been tempted to use temporarily until I gain a few more lvls and could get higher into the rage tree. This is how my skills stand atm: http://www.torhead.com/skill-calc#100ZZGbRrdbR0M.1 I was thinking of taking the points out of payback and putting them into annihilations 'quick recovery' because smash is used a lot in the rage tree. Smash surprisingly can do more damage than all the single target abilities when used right. Right now since they always crit for me I'm seeing them doing around 1250 per target average. (again around lvl 33, 3 lvls ago that damage was still in the 1k range). If smash stuns a target than it's always wise to follow up with a pommel strike which is the highest damage single target attack you would have at that point. It requires a incapacitate which is why it would follow a smash if a stun was applied to a target. There's the obvious part of always using battering assault on CD to build up rage. Charge is the next best thing if you can use it though obviously usable first to open combat with. Assault is last on priority and should only ever be used if more rage is required that is not available otherwise. I also have sweeping slash now so if there are around 3-5 targets grouped up I'll do that right after the smash --> pommel strike (if it applies). Ravage has been coming right after those and preferably on a target I know can get stunned by it which reduces the damage I take since they're disabled. Force choke is great on elites and strongs since it'll disable them for a bit and it builds up the shockwave stacks (plus rage) which more than makes up for any aoe damage loss you may of had by using it on your next smash. At this point in the game I also have a CC against droids which helps but be mindful of you or your companions aoe. For single target damage abilities I think I've been following Ravage -> smash -> scream -> Obliterate (reverse obliterate w/ scream if you need to make a smash very soon to promise it'll crit). Vicious slash is always the filler and the 15% crit boost should help a great deal. Berserk for the tree is really nice since the free cleaving vicious slashs will have the 15% extra crit too. Retaliation should also be used since it's off the GB so just try to throw it in as much as possible. (Mid GCD on others abilities is a great time) Also remember that a rule of thumb regardless of skill tree is to make active use of cloak of pain, saberward and obfuscate as they really do reduce a lot of damage you would take. Interrupting targets helps too which surprisingly not a lot of people do. They all have relatively short CDs. Save call of the force for drastic situations but always use a saberward before it so the free refresh on saberward CD isn't wasted. Remember this is how it currently applies to me at level 33. For the most part all of this has remained the same my entire leveling experience and I only change up as I gain new things such as sweeping strikes. I think we are some what of a stat reliant class which being level capped would help. I noted that accuracy does not just affect out MH weapon but also our OH thus being higher level should help you as you'll have more chances at gaining accuracy on items. At level cap you'll also finally have all your best bag of tricks and your abilities should be scaled to their proper damage scale that was more than likely where they were compared to other classes at. And sorry for the wall o' text but it's what you asked for

The class starts out weaker than it actually is once you're a higher level. Once you get around your mid 20's the class takes a decent step up and only progresses to taking another step up as you continue on to the level cap. In short the beginning levels of a SW are lackluster and a poor representation of what you'll actually be like at higher levels. Your CCs doesn't come until later too. All poor design concepts in my opinion as it deters people from playing it because they don't realize the potential but another thing to keep in mind is the class also seems to have a design about needing to be on a the ball with all the abilities you'll need to use. I personally have not had any issues with my Dps. Vette is a powerhouse but I've actually been ahead of her and in general everyone I've been in a flashpoint group with. You need to learn and master the priority system in order to be efficient at damaging. I am curious as to what skill tree you have been using too. Annilation starts out weak until you reach probably the 30's level range. Carnage has been what most have gone for until that point if they don't plan on sticking with it and even that skill tree doesn't get great until you're a higher level. Personally I did the one thing most haven't been doing which was go up the rage tree. For whatever reason a lot of people think since it's a shared tree it's stupid, crappy or even not a unique enough of a tree but it's actually been really good to me. The tree itself for the most part is not unique but that doesn't mean there aren't any unique factors to it or that its damage sucks. Many don't factor in that it's scaled with the second saber and you'll be combining it with other skill trees unique to the marauder rather than the juggernauts combination with it. As I said I've been equal to if not better than others on dps with it so imo it is good.

What does it do exactly?

I've had mine vanish occasionally after a flash point but found that if you right click it should come back.