They both have their drawbacks. I own both of them and I told myself I would not buy the Vita until I saw some serious software support from Sony. (I still bought it at $180) I know the hardware Sony produces has plenty of potential, but recently, that has been it. They don't follow through with great applications to take full advantage of the capabilities.
Example: I can't stream from website like di.fm, Grooveshark, and other adobe player sites. It's you tube, and that's it. (unless you're counting that worthless Music Unlimited Application that sucks because it limits you to Sony published music) I know this console is not a smartphone, but it has the tech to do everything a smart phone can do except work on the GSM or Version Networks. (Maybe the 3G version can) The damn thing is a tease, while it should be an alternative option to a land phone (compete with Vonage/magic Jack), for those people wish to use skype to make calls. This an example how Sony misses out on opportunities to make trends instead of following them.
They could have done the same with PSP & PS3. If it's lacking support from some type of media, buy it from independent software developers and then sell it as extras in the playstation store. Example: I Love that flac codec and no console out there supports it. Sony, make it happen by enticing the creator to sell it $.50-.99 cents on the Store. I would pay that, if part of is going to the creator of the codec. Example for the PSP: The lag on the Final Fantasy Tactics is horrible, I needed to crack the damn thing to apply a patch. (Sony to the rescue, by accepting 3rd party modifications on some of the games) Sony should accept that the PSP is a victim of its tight restrictions, they should have turn it around by creating a marketplace for passionate gamers(who can code and modify games) & and game developers to come together. Sony misses on opportunities to create a devoted & loyal fan-base that would follow onto the next line of consoles.
I believe that if they would make their consoles highly customizable based on the Korean model (where one is sold the vanilla experience, but one may purchase plenty of upgrades to customize the experience to be unique to the user) and include in the mod community you find on PCs (pay for their work and regulate the improvements) Sony could create a massive following (who have a high attach rate). I can see them shifting the tables on Nintendo & Microsoft who would be looking at to copy this model. Alas, I know I'm nothing but a dreamer because Sony shows no signs of loosening its tight grip of restrictions that it places on its hardware.
PSP Grades: Hardware: B+ Software: C+
PSV Grades: Hardware: A Software: C+
PS3 Grades: Hardware: A- Software: C+
Gradescale rate: F-> A+ (Based on year of release compared to PC/smartphone capabilities.)