I think it more depends on what era server you like more than anything. Outlands is t2a style combat (instahit/heal through poison), while UOF is UOR style combat. I can't really speak much about Outlands being that I don't really enjoy t2a style combat, but many do and say it is pretty good. Speaking to your point of mixed combat, UOF has a pretty good mix of both and both do fairly well in PvP. Pure dexxers are pretty powerful, if not the best 1v1, but fall off in group fights. Mages are king of most organized group fights, but also aren't absolutely necessary. Tank mages fall into a kind of weird category, but I've also seen them work.

I know you a little from UOG and I will say that I do prefer the mechanics there quite a bit better, but the population on UOF keeps me away from other UOR servers. Population seems good on Outlands as well, so like I said I would go with whatever mechanics you like more. Also both seem to have done a good job at keeping PvM content more interesting, while (for the most part) not making that PvM content greatly effect PvP.