The KeyTwo is out now, but I'm not terribly interested in paying £600 for a phone - any phone. I got the Key One Black Edition for just over £300, and that has the upgraded RAM and memory, so it's rather more future proofed - I'd always suggest that over the standard silver edition unless you were going for the KeyTwo. They've brought a lot of the good stuff over from BB10, such as the Hub, which is a universal inbox for apps, emails and so on. It's not as good as the BB10 one where you could reply in line for something like Whatsapp, but it's still pretty decent.
The biggest point of difference in terms of convenience has to be the launch keys. Assign T to Twitter from the homescreen, and just hit the button to launch it, rather than scrolling through screens. It's terrific for that.
It's a mid range phone, not a flagship, but it doesn't lag or anything. Niche product, for sure. But a bloody good one.