Mercenary

The Mercenary has 3 skill trees that you can spec into. Here's a little description of them (leaning towards pvp)

Bodyguard - Healing tree, don't know that much about it, supposedly decent but not quite on par with inquisitor/consular healers atm.

Arsenal - High DPS "caster" class. Has very high burst damage and good AoE damage, but is lacking in mobility and cc. If you want to play Arsenal well, then you need to be standing still casting (Tracer Missile) whenever you have the chance, basically a static turret. Has some problems dealing with melee classes and contrary to what a few people think, it is not a good kiting class, as you don't have enough stuns snares or movement impairing effects, and you need to channel a lot, so people can just move out of LoS or interrupt you. But overall extremely good damage and one of the best DPS specs right now.

Pyrotech - This is a DoT tree that is more mobile than Arsenal but has much less burst damage. You want your target to be burning at all times (Incendiary Missile) as this does decent damage over time and increases the damage of a lot of your abilities. It is more of an instant ability class rather than casting like Arsenal, however some abilities will still need channelling such as Power Shot and Unload, but overall it does have more mobility and you can fire off your attacks on the run. The general consensus is that this tree is inferior to Arsenal, however it is more balanced in terms of blaster to missile usage, so if you dislike the missile spam of Arsenal and want to use your duel blasters more, whilst lighting stuff up, then Pyrotech is an option for you.

A lot of people (in various forums) seem to be debating which healer is going to be best, so to break it down a bit based off their skills and skill trees I feel its safe to say:
Once you choose an Advance Class (AC), it cant be undone, but you CAN respec your skill trees for any one AC. keep this in mind when choosing. All of the healer classes have different resource systems, but each of them has at least one small, spammable, "free" heal that doesn't use any resources. It won't be enough to get through tight spots, but it will make resource management tolerable.

SI sorcs will have castable damage shields (think wow priest PW shield) and channeled or cast timed heals (mostly reactionary) with a recharging, mana-esque resource. It has a battle res. Its dps respec is a typical caster: cast timed burst spells, as well as some channeled DoTs and large aoes.

IA opers will have a single target HoT heal and then cast timed and reactionary instant heals with a constantly recharging energy system (think wow rogues). It has the ability to stealth and it has a battle res as well. Its dps respec is a melee class that can specialize in burst damage or poisons. It has some ranged skills, but not enough to keep it out of melee range effectively.

BH mercs will have a reactionary healing shield castable with multiple charges on a single target (think shammy earth shield from wow). and then the typical healing skill set. It uses a heat system that builds up with skills and dissipates over time, with a few mechanics to help lower it back down and a number of heat-less skills to keep it low. It does NOT have a battle res. Its dps spec is a ranged class that has some CCs and can either burn through all its heat in a quick burst or use a more sustained rotation to keep heat low (pvp vs pve maybe?)

It appears you can pick and choose from the specialization trees, but i doubt you will see such a mix too much in pve, but will likely be prevalent in pvp for a mix of survivability and dps.
I know some people only care about numbers, but for those who care about how a class plays, I hope this helped.

"I am wanting to play a merc bounty hunter as my main and a sniper as an alt. I am torn on who to give Armormech and Armstech. Has anyone in beta found one of those crew skills that is hands-down better for a bounty hunter? "

They have already announced that crafted items will not be better than gear from operations (instances) or pvp, so I would sooner recommend biochem or cybertech for consumables and gear mods if you plan on doing either. It might be convenient crafting gear to start with, but long term it will have less and less personal use. (can still sell to lower level characters who don't want to work for it i suppose)

I'm palying with my bro currently lvl 24 and he went power tech side and I was going body guard but he's more of a body guard type than I am as he deflects up too 50% of damage very mobile, best to play as a stationary turret chess piece, there's really not enough healing can be done when your being interupted and the firing is reduced to just a positional operation as in pvp senerios, you want play the in the back ground assisting, aiding others snaging, clearing, and dumping additional damage. and aid in healing a damaged toon. Now I have my skill in armour smithing so I have some stats to play with. for my bro's char aim+ and (defence) when optional, works best for what he likes in game play. I tried this as well, It works well but I don't think it quite brings out the toons ability.
I'm going to make a few suits to play with and try endurance as the primary focus perhaps defence or power. The crafting of armour is huge as the tree of unlocks expand, the consumption of credits and resourses is huge, esp in the begging as you only have the one companion and your scavaging resourses. I wanted to focus on crafting earlier on but ended up too high of a lvl for the area of missions, as gathering resourses requires lots of combat. I ended up rolling through the missions with ease, to obtain 5% exp :) but made up for it in pvp.

I think the options are great in the game, and there is alot of room for different types of playing and templates I might also re-skill my tree around as well. I won't put down this build as it's finding the right senerio's to operate within in.

In the last beta weekend I played a commando, my friends are going dark side this time so I will likely be playing a Bounty Hunter: Mercenary as they are very similar.

Run-n-Gun tactics, lots of on the move AoE knockdown effects and the ability to heal in a pinch in a group makes for one HELL of a class.

I dominated the first 2 flashpoints on my commando, I really look forward to seeing how the Mercenary does!