It's a tough call. I own a vita and am very happy with my decision to buy it. I love the games for it (VLR, although thats on the 3ds too, MGS HD collection, P4G...etc.). I never had those games on ps2 so I was able to enjoy them more fully. Same goes for the upcoming FFX games. And the games currently on the lineup for this year look good (Y's, Killzone, Tearaway, etc.)
But looking towards the future, unless sony pulls something massive out of their ass at E3, the 3ds is probably going to get more "good" (although I realize thats a subjective term) games. At least if it keeps up its current trend. SMT Soul Hackers and SMT IV alone would make me buy a 3ds if I had the money and wasn't saving for a Ps4.
My honest opinion would be to wait for E3. Sony has stated publicly that they know they've maken mistakes with the vita, and have started (albiet weakly) to turn around. If they have another bad showing for the vita after ADMITTING they have a problem with it, then I would say that you can safely buy a 3ds with no regrets. If not, I say take the plunge and go for the vita. Hope this helped!
"Is this board all under 16? except for me and (sailor)goon, which are on each side of the trolling." -Shadowfxd2
I own both and love both Nintendo and Sony equally. My comparison is unbiased as I have seen the good and bad of both and have played the two handhelds a lot. I would say for you vita is the way to go. Why? You own a ps3, and will likely buy a ps4, am I correct? The vita is going to be the best thing ever for you. Several games have cross buy so if you already have em on ps3, you have them on vita. Then you have cross play so you can get game saves and play them on the vita and it would be no different than playing on ps3. Lastly you have remote play which comes into play with the ps4, if you can stream ps4 games to the vita, it's like having a portable ps4. The vita also has a great collection of indie games and upcoming 1st party games (pretty great 1st parties already out though) although I will admit, the vita is severely lacking in 3rd party support. Other than that and the price of the vita, it's a pretty great system. The 3ds is the cheaper system and it has an abundance of great 1st party games like Kid Icarus and Super Mario 3d Land. But is, again lacking in 3rd party games. Anything to do with downloading games or playing online is either done poorly or simply not enough. TL;DR: Get the vita if you have the money and own a ps3 with a plan to get a ps4.