This is a pretty complex discussion. The Wii-U is fairly simple in how it works and we know almost everything about its capabilities. The vita/ps3 however is way more complex with strange terms such as cross-play, cross-save, remote-play, and cross-controller all being misused and jumbled into one. In addition we have had very little hands on demos with the technology. I've kept up with the Vita since it was first rumored and hopefully can better explain Sony's side of the story.
Cross-play
Cross-play is the ability for a Vita player to play against a PS3 player online. This is nothing like the Wii-U because the Wii-U gamepad is not a stand alone system. Cross-play was available at launch with Wipeout 2048 and was announced back when it was still called the NGP. Things get slightly more complex when the Vita player is in the same room as the PS3. All of a sudden Wii-U like gameplay is possible such as with PSASBR. So far though cross-play has stayed true to its roots and is not deviating from online multiplayer shared between both systems.
Cross-save
This feature is another one not possible on the Wii-U since it is nothing like the Wii-U. Cross-save allows a gamer to be playing on the PS3 and seamlessly transfer the game over to the Vita for out of the house gameplay. When the gamer returns home he can reverse the process and keep playing on the PS3 where he left off on the Vita. This is similar to the Wii-U working when the TV is off however the game is actually playing on the Vita instead of being streamed.
Remote-play
Remote-play existed all the way back with the PSP allowing gamers to connect their handheld to the PS3 either over the internet or locally. With the Vita having all the necessary buttons it can play PS3 content and games however this feature is very limited with few games supporting it. This feature is exactly the same as playing a Wii-U with the TV off except the Vita is not limited to be within 24 feet of the PS3. The difference is that not all PS3 features are supported and the data transfers at a slower speed.
Cross-controller
Finally I am talking about the actual Wii-U like experience on the Vita/PS3. Cross-controller allows a Vita to hook up to a PS3 game and be used as a controller. This replicates the Wii-U experience in theory and was first shown off at TGS 2011 with asymmetric gameplay of LBP2. Recently it is being demoed with LBP2 which is what has started this whole Wii-U verse Vita/PS3 debate. The connection between the Vita and PS3 is local and not using WiFi as many people claim. This means the data transfer between the two systems is almost instantaneous similar to the Wii-U. Right now only one game is coming that supports this, LBP2.
So theoretically going by the hardware both the Wii-U and Vita/PS3 are very similar and capable of almost the same things. Software wise it doesn't take a genius to know Vita/PS3 features will be underused and hardly supported though. Let's wait till cross-controller is released with LBP2 DLC before we pit Nintendo and Sony against each other on this.







