If you follow the forum you will see that a lot of devs are having similar problems.
These range from storage issues to layout issues or other incompatibilities.
And as far as I see the main issue is OEM Firmwares are so highly customised. Mount points for external storage locations are different in different devices, soft buttons or toolbars, devices reporting the wrong screen attributes, text colors and background colors etc etc.
As far as issues with Android as an OS is concerned (go here and see if it is a reported/known issue):
Issues - android - Android - An Open Handset Alliance Project - Google Project Hosting
It is not perfect.