I come from a shitty Android phone.
I love my N9 but must admit there are quite some limitations, especially in terms of customization.
To name a few:
* Cannot see calendar events "widget-like", or in the "screen-saver"
* cannot disable weather "widget"
* Cannot see clock in the standby screen while playing music
* Cannot see more than one MFE calendar (bug ?!)
* No gmail push support - "up to date" option on MFE gmail account will drain battery
* No google map (Ovi map is incredibly slow)
* Browser is ok, but user-agent is usually recognized as "desktop"
* idlle leakage bug
* it lacks some key apps
* Not able to resynch MFE after a failure

The rest is good (to me):
* Design
* camera
* smoothness
* SIP VoIP integration


In the end, I would have a look at ICS... However, my point is that I would be more than happy with an Android 2.3+ release... !