I am totally on the pure Android bandwagon. I currently have an Epic, and loved it until Sprint pushed out the 2.2 (Froyo) update. Now my phone is slow, short-lived (battery) and really not that great as an actual phone. Thus, I am moving to the Nexus S, sans Sprint bloatware.
I am of the belief that Google wants to make a great mobile OS, because they need to. I also believe that Sprint, along with all mobile service providers use their customized Android updates to push you to purchase new hardware.
I do, have an easier conversion than most, however. I am going to extend my contract to add a new line and I also have a discount source for the phone, itself. This eases my conversion pain significantly. Honestly, if I wasn't in this boat, I would tough it out on my Epic until my contract was up too, but I'd hate every minute of it until I found a way to put Cyanogenmod on it.