Vita isn't cheap. VitaTV will look like crap probably, it can't push 720p (hence shield does). Will this push 720 or 1080p video with all formats supported like android? I don't think so. And the TV's expected price of $150+ won't hurt a $60-100 Roku etc for movies and all the content they have (more than I can take the time to watch).
Unless I don't understand Vita TV it seems to be an added device. So portability is out unless you ALSO buy a regular Vita right? So you're better off with shield to cover both portable, portable movies etc, PC to TV, all android games vs. Vita's rather weak library and no developer support if GDC 2013's 2800 devs are to be believed (nobody cares about Vita, hence this TV console version to try to spur more sales of a failing Vita).