I had a 9.7" 128 Pro from... basically when it was released until September of last year, when it became clear that Apple wasn't going to do a significant upgrade. Mostly it was because I wanted the new. That sucker was as solid as when I'd bought it, maybe a few more Safari page reloads but, otherwise, just as fast as everything else. It is, and was, a hell of a machine. In fact, I gave it to my wife and she took it on a business trip with her with her laptop also and she's said that, next time, she's going to leave the laptop at home. I think that speaks volumes, honestly.
I'm an app developer and my client had moved entirely to 11" Pros so, it was tough for me to support them with the 9.7" when they reported stuff. But... I mean... really... that was just my excuse to upgrade. The 11" is... well... everything I always wanted a Baby Pro to be except for still not supporting two "normal" width size-classed apps side-by-side in landscape (like the Daddy Pro does). I love the screen refresh rate. I like the lack of home button. I really love the weight when I remove the folio. And it's just so easy to read on. But, had Apple in September announced they were going to release a new Pro in March, I still would have waited because the 9.7" did everything I ever asked of it.