See the official feature highlights and full specifications here:-
http://store.sony.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&storeId=10151&langId=-1&productId=8198552921666433223#specifications
The sensor is the same one used in the K-5 and K-01. It has a fine and large EVF with 100% coverage as EVF is actually the policy of Sony. Furthermore, the Full HD 1080p at 60 frames (per second) capability should be noted. As usual, Sony SLT is able to continuous auto-focusing and track the subject during video recording. So, every time whenever some Pentax boys still told that K-01 is new and strong in video recording, this really makes me laugh! :-D Indeed, what to rave about actually? H.264 motion compression in MP4 was what could be found in the old Pentax Optio MX, which I also had. Besides, re-focusing upon the press of a button was what the Canon DSLRs could do a few years ago! Nonetheless, we should also note that lately PF has commented that the AF is really slow under the video mode, too.
Of course, there are a lot of features that exist in the A57 but are missing from the K-01. The size and weight of the two bodies are close. Price wise I don't think the difference is huge. So, if you are just not a die-hard old fan of Pentax but have to choose a *large* new interchangeable lens camera based on features, price and performance, what would you choose? (I think the answer is clear cut!)