I have a retail review copy of the Vita game.
I can confirm that the Teensy count is 615, which is 85 less than the PS3 version. The Invaded levels have three Teensies a piece to earn, so that's 28 levels not included. That's assuming that all of the missing Teensies come from Invaded levels, which I can't confirm because I have not unlocked them all yet.
Story mode and Back to Origins Teensy counts match on both games, and the Vita exclusive Murphy levels don't have Teensies so far as I can tell.
The Invaded levels take less than a minute each but usually require a few tries, so there is a minimum 30 minutes of content missing. I've been getting them done in a few attempts so realistically it's about two hours.
Still working on unlocking the Murphy levels, so no comment on how that content stacks up.
Opinion. Crummy that they haven't mentioned it, especially after that press release that floated around in May said the Vita version featured all of the content of the console versions (though I'll admit that that press release was never sent to me, nor did I ever see it on an official Ubisoft outlet... it was translated from Eurogamer Spain IIRC).
Still though... it's a handheld port that costs significantly less in North America. And it's really great aside from the missing levels. I would have been satisfied with the amount of content at the given price point.