I've had each of the full size iPads, and they've been great. I bought the iPad 4, and while it was more of an incremental upgrade based on my usage, it was well worth it.
That said I've always embraced tablets. While waiting for Apple to decide if they would build a more portable model, I've had a couple of Galaxy Tabs and now I've got a Nexus 7. It's a terrific model, being pure Android it updates automatically as each new OS rev is released. Pushed out to the device it loads it in the background so all one has to do is click on install when prompted, and it installs, reboots and you're ready to go. I simply couldn't be any easier. Google has caught up to Apple when it comes to ease of upgrades and updates.
Finally Apple has responded with the mini, and I enjoy that one as well. About the only drawback which is merely personal preference is it's width. At 15mm wider than the Nexus 7 it's not as easy and comfortable to hold, and I have large hands. The lower resolution as opposed to the N7 is noticeable, a bit annoying but not bad. All in all I'm enjoying all three and use them quite a bit more than I orginally anticipated.