There's 4 classes of ships, only 3 are currently usable for subscribers who got early access, and one of those is only usable for people who were subscribers back on (and since) november 1st. Unfortunately, I dont fall into that category, so I only have access to scouts and strike fighters.
Scouts are like our light fighters here. Very fast, pretty manuverable, but light on defense and offense. Scouts have extended sensor range though, and advanced communications equipment that lets them basically share enemy positions with allied team members (your extra sensor range means you can see enemies on your minimap/radar at further range, and then anything you can see is communicated to allied minimaps/radars within a certain range of your ship).
Strike Fighters are the standard/heavy fighters. The default strike fighters have 2 primary weapons and 1 secondary weapon (as opposed to 1 primary and 1 secondary for the scouts), while advanced strike fighters that you can unlock after winning a few matches have 1 primary and 2 secondary weapons. Primary weapons are lasers/cannons/guns, secondary weapons are missiles/rockets and such. Strike fighters are less manuverable and slower than scouts, but have more armor/shielding/firepower.
Gunships are big and slow, I'm not sure what their primary/secondary weapon setup is either. However, I know that they get a unique weapon type called a railgun. When you activate the railgun, you go into a first person 'sniper scope' view, then you hold down the fire button to charge up the weapon. When you release, it's an instant hit weapon with a 15k range (as opposed to the 3-5k of other weapon types) that can kill most enemy ships in one or two hits.
Gunships are currently only available to people who were subscribed on and since november 1st. A lot of people fly them, and a lot of people do well with them (probably because it's easy to snipe noobs), but aside from the rare case where I'm caught offguard by a gunship I didnt notice early, I dont typically die to them. Gunships, for me, are one of the easiest enemies to kill, because they cant outrun or outmanuver anything else and are pathetic combatants at close range.
Bombers arent currently available to anyone, but will supposedly be released when the expansion goes live for all players in january or february. From what I gather, they're primarily focused on heavier secondary weapons like torpedoes, and are designed for taking out satellite defense turrets and other stationary targets (they'd probably do well against gunships too).
Personally, I fly a scout all the time now. I tried strike fighters but dont do nearly as well in them. Most games I wind up with 8 or 9 kills and 0 deaths.
Most players are complaining about the controls and how much they suck, but it's almost identical to freelancer flight and aiming, so I've been doing pretty well at it. There's some things that we dont have in FL though, including power management - you can alternate your power levels between weapons, shields, or engines (and I started doing even better in matches when I began to actively change my power levels to suit the situation). I'll run with power focused to engines right at the start of the match so i can speed towards objectives and cap them early, then switch to weapon power whenever I'm trying to gun someone down, and shield power whenever someone's on my tail until i can shake them.