I'm not disappointed at all in the 925/928. I prefer the design of the 920 to both and they aren't really appealing to me, but I'm not disappointed. As far as I'm concerned Nokia is doing an excellent job.
I AM really disappointed in Microsoft. They aren't innovating quickly enough and the experience on the OS, while better in many regards than the competition, still has some very important missing features which shouldn't be difficult to implement. Notification center, independent volume controls, generally weak and buggy Xbox Music/Video/Podcast apps, underwhelming integration with Windows 8, etc. All items that constantly remind me that I'm using a platform that shouldn't still be using the crutch of being "new", MS has to get it together and solve these issues and a once-a-year update cycle isn't nearly frequent enough.