First, I'd like to congratulate you for your awesome thread, you make really good points while not being biased towards any side,with that said now my opinion.
I'd like to point out that I have no opinions about UI, while I do agree that ease of use and a pretty UI is really important for some people, and that it also could attract more casuals gamers, my opinion will solely be about the games for the consoles being discussed.
The first next gen console that i bought was a PS4, which I got at day one, personally I'm not much of an online gamer so I can't comment about online capabilities either, the games that I got were Killzone SF, knack and AC4,
Killzone delivered a different experience for me since I had never played a Killzone game before I thought it was above average, but maybe that is because I was new to the game, knack I didn't even finish so I can't say much of it, AC4 I only got it because I wait at least for the first update to be released on any Ubisoft game for PC before I get it, surprisingly the game looked great on the console, I couldn't find jaggies or anything that bothered me so I ended up playing the game on the PS4, at this point I was really content since I believed that most games would have this level of anti-aliasing on next gen consoles, but my joy was short lived since I haven't found any other game with that level of aa on the consoles, so far I've enjoyed the console, it's got great games specially TLOU which I had never played before provided pretty visuals and an epic storyline.
The Wii U I got shortly after PS4, like any other console I only get because of it's exclusives, but this applies more to the Wii U.Its games have not been the best if you compare them to past gens, but they are enjoyable none the less, I loved HW and Bayonetta 2, patiently waiting for Smash.
My Xbox One I traded it for my first PS4 not long after getting the Destiny bundle, got me Forza and Ryse, Forza I loved since I'm a fan of racing games, Ryse i thought it was good but didn't finish it, plan to finish it on PC later,I was not going to get an X1 until Scalebound got realeased, so right now it's not doing much will sell it after I import a Halo MCC bundle hopefully I'll make more use of that one.
Overall I personally don't feel like any console has delivered a real next gen feeling but I'm still loving them all.
My only complaint would be the jaggies and screen tearing, which I thought would be fixed this gen, wished they could use the almighty sgssaa for a crystal clear picture that i'ts just me though, I hope you excuse my long comment but I just wanted to provide my honest opinion about these consoles.