Can't say too much.
It has some new shine. If you are looking for 5 brand spanking new ATs to play, you are probably going to be disappointed. If you hated the combat system in CoH, you're not going to make friends with CoV.
4 of the ATs are hybrids of exiting system, BUT, they do play differently once you advance a bit. One AT, is completely different from CoH - Masterminds. Masterminds rock. If you like role-playing, CoV gives a lot of scope for that.
There is a going to be a fair amount of crossover content, which I can't talk about publically. One hint - IOP. Oops, I've said too much. The zone that CoH did a story on recently is a CoV/CoH crossover zone (Siren's Call). Both Heros and Villains can go there. Should be fun.
Did I also mention there will be SG content? (But that's linked to IOPs)
In CoH/CoV, generally:
Solo (and <4 players) = Grind.
4players = Fun
8players = Awesome
Unlike WoW, CoH/CoV has enough features to get a team going rather quickly. Even random teams now are half decent. In random teams, generally you can complete missions on the lower difficulty. But with teams of players that know each other, generally the mission difficulty one below the top is do-able _just_, the top difficulty you actually need to work as a team
At the moment, coalition was the best thing for us aussies. We have a good coalition with SAS, PCA, and to lower extent Trashgallery/Rainbow Force. There will be at least 10 regularly players _outside_ of SC on day one that we will be in communication with. So I doubt you'll be soloing on day one.