A good user experience has nothing to do with looks....make the crap fast (especially on mobile) and as easy as possible to use. That's "the secret".
(I'm unable to use apps with imperfect looks. An ugly icon is enough. It just drives me crazy. I have to delete them. I'm strange that way and most people are probably not like me but still … I can't really believe that looks don't matter at all.)
Edit to add a little tangent: That's not to say that custom "beautiful" interfaces are always desirable or easy to pull off. If you don't have it in you the end product will be a horrible mess. (Especially for all those poor picky people like me.) Sticking to the stock UI is probably the best idea in the vast majority of cases. Going custom requires serious talent and an unquestioning attention to detail. At least if you want to please me.
Good design doesn't always mean as shiny as it could get. Minimal approach such as Windows Phone 7 UI design is also consider as a good design.
I understand what you are trying to imply here. I just realized that I also should have given some comparison on shiny and minimal designs as well. Thanks for mentioning about this. :)
Yes, things being fast and easy to use are part of a user experience as well, but they don't make up the complete user experience.