Hmm ...
What I find disappointing in Fiesta is the lack of skill. I've been studying up on Shaiya lately, and you can do so much there. Backflips, sidesteps to avoid attacks, etc. It requires skill to manipulate. I've compared a Fiesta guild war and a Shaiya guildwar, it just looked so ... different ><
BUT, I think Fiesta has a really great community. In companies like Aeriagames, they have tons of people like game sages and GMs, but Outspark has really little. For the little people they have, I think Outspark is doing very well, and their GMs are very nice too.
Also, Fiesta's community is really nice. Great guilds, great people (at least most of the times) I can't compare it to much, since Fiesta is my first MMO, but I think it's pretty nice =)