I was in the same position but figured that the K2 already does most of what I need so I went ahead and bought one. I just wanted the wikipedia and web access, I also liked the idea of the TTS. I'm sure the K3 would offer an incremental improvement in a slimmer package but I just didn't want to wait any longer. They're also selling the K2 cheaper at the moment
I could wait for more products to be released but figured I'd been waiting for long enough already. Of course if I can't get it to do everything I want in the first week then it will go straight back and I'll wait for a better product.
I'm now impatiently waiting for delivery.