When all is said and done, all the consoles with have a decent library of exclusive titles and it will come down to personal preference.
I have all 3 consoles this gen and without a doubt, the Wii U has gotten the most play time from me - but then again its been out the longest and I bought it close to launch...whereas the PS4 and Xbone I got much later.
I rag on both the PS4 and Xbone - but I honestly enjoy them both and don't regret getting either. I will say this though, as of right now I am playing my xbone much more than the PS4 - this is primarily due to Killer Instinct. Also, Sunset Overdrive is much more fun than I had anticipated. I am not a fan of games that cram attitude down my throat - which this game does - but the control is just a ton of fun and more than makes up for it the in-your-face schtick of the game.
Also, in terms of which is a more powerful system I could really care less. There's a lot of factors I take into consideration when getting non-exclusive games.
For example, when I got MK X I could have got the PS4 version, but I decided to get it on Xbone because I'd rather not get 2 arcade sticks and would rather have one for Xbone for Killer Instinct - so I decided to get MK X on xbone. I don't know if the PS4 version is "better", but I have no problems with the xbone version. True, SFV will be a PS4 exclusive I guess...but I've always felt comfortable playing SF games on a pad, so I have no problem not getting an arcade stick for that in the future.
Same goes for Project Cars. The PS4 version might be a tad better (I have no idea, just speculation), but I will probably end up getting it for xbone since ideally I'd like to get a force feedback wheel, which I could also potentially use for the Forza games as well, if I ever get those.
On the flip side...I'll most likely get the Witcher for PS4. Same with Arkham Knight and MGS5.
Anyway, all the systems have their pros and cons. It's a shame Microsoft kind fucked up early before the launch of the xbone because I think it's a quality system with some good content - but Sony just handled things so much better early on and they are still reaping the benefits of that.