There are many reasons for not upgrading an iPad.
I was quite happy with my iPad UNTIL I upgraded to iOS 5. I then lost my ability to sync my iPad with my Mac. The new Music App seemed quite ill designed and among other design flaws, there is no functionality to listen to podcasts a double speed,as in the previous version, which I did often with podcasts to inform myself for trainings I led. To add insult to injury, all my podcasts now play a 1/2 speed and so, the iPad is effectively useless for listening to them.
Besides not being able to update content on my iPad without using e-mail, Dropbox, or iCloud, I lost a lot of my user data, e.g. samples in iBooks, in the process. Yes, I could download them all again, but I had quite a few and no list of them to work from, because why woul I expect them to be deleted. All this only to learn that all the backups I had been making using iTunes, DID NOT INCLUDE user data, including the book samples!
After several attempts at getting help from the "Geniuses" at the Apple Store, and either reinstalling or having them "professionally" reinstalling the system, I am left with a severely crippled iPad that frequently crashes, and that I cannot backup or sync.
I would be ecstatic to restore it to pre iOS 5 status, when all worked perfectly. The only other wish I have is that I had bought Keynote, which I had no use for at the time, but which would be useful now, but cannot because it is now only compatible with iOS 5.1!
Just my 2c.
Love my iPad just not the lack of control over it.