The space combat has the potential to be really good but lacks depth at the moment. In most other mmo's during combat you're looking at least one full bar of powers/spells/skills, in STO it's basically just your weapons and upto 3 bridge officer skills (tactical, engineering and science officers). Which I wouldn't mind if other things were spot on like sound effects and ship control. Obviously it's still beta and the more cosmetic things may get polished but the basics of front and aft weapons and the bridge officer skills will remain the same.
Group/public missions are pretty epic the first few times, seeing phasers and torpedoes flying everywhere with various ship classes flying around looks really good. However at the moment and from what I've seen so far combat remains shallow with few if any real tactics apart from get in range, keep broadside to use forward and aft weapons at the same time and circle enemy until they're dead.
Saying all that sounds negative but I've only been in 4 of the 2 hour sessions so far, so I've had a maximum of 8 hours in game - obviously far too little time to judge a mmo accurately. And 2 of those sessions were at 2-4am uk time so being like one of the living dead during those sessions may also cloud my view