This is the version where they've finally united the single- and multi-player modes.
(Which basically means all the bugs and annoyances from multi-player have been applied to single player too.)
The pre-release is already available for anyone wanting a sneak peek - tempted to have a play but I haven't yet.
* Removed the downwards knockback while drowning.
* The "Mojang" splash screen when opening the game appears for 1 instead of 3 seconds now.
* Fixed Unbreaking-enchanted tools sometimes breaking and then re-appearing a few times.
* Fixed blocks disappearing when placing them under yourself and jumping.
* Wooden tools can be used as fuel in furnaces.
* Boats are not broken by lilypads anymore, are less glitchy and more responsive, and - when broken by a player - they drop a boat again.
Plus a whole lot more if you follow the source link for that quote.
I've been playing the snapshots pretty much at every release. I'm enjoying proper survival mode now (as opposed to just playing on Peaceful), although not so much solo, and I've been on Teh 2012 a little bit but would much prefer to be doing so with peoples.