From what I've seen, the interface looks extraordinary. If I was running RAW/core or even a slightly modified/expanded game, this'd be an insta-buy.
Unfortunately, I'm running two campaigns: one with several UA and house variants (including spell points) and one using RAW from Eberron, most "Complete" books, and the XPH. RPGX doesn't handle multiple rulesets or spell points, at the moment (both are supposed to come with the 1.1 patch/update). And I'm just not understanding much of the customization features, or thrilled with the back-end data design that I do grok.
Right now, I'm sticking with PCGen. I'll continue to putz with the freeware DB and keep my ear to the ground on what others can do with RPGX. By the time the 1.1 patch rolls out, I'm betting that I'll have a much better idea. I really hope the feedback is good, though. The interface is beautiful, and the screen shots have already started to win over my players. Besides, as a .NET developer, I'm biased toward that platform.