I've been interested in this phone/handheld hybrid since I heard the early rumours, so far all the complaints I've heard include;
-Divided game market (that should be fixed when PS Suite arrives)
-Lack of 720p video recording (although it's technically capable of it)
I personally don't believe that the lack of a dual core processor would cause many problems in the near future, or at least for the length of a regular contract, we've all seen what the PSP is capable of & the Xperia Play is much stronger, probably still stronger than the 3DS so I think that kind of proves that it's specs shouldn't be a deal breaker.
Personally from the look of things, if SE & SCE can deliver something amazing through PS Suite like a plethora of PSOne & hopefully PSP & even PS2 games, it could very well be like bourbon; Gets better with age.
Anyways, I'd like to hear from some of you guys if any of you have gotten any hands-on with it, I don't think that it's even started being shipped to Aus yet so there's no way I can get hands on time without importing.