This is just my opinion, but:Leveling is realtively easy. I am a casual solo player, and do not find it very difficult
PvP is okay. FvK, and KvK matches only (space and ground)
PvP matches are fun, but still broken currently.
No real 'Open world PvP' yet.
No 'PvP Exposed PvE' (ie its basically just WoW BGs)
Too 'safe' and meaningless for me right now.
You have to start a Fed toon to unlock Klingons.