Got a set of Loophole 56mm V-Cuts from Library the other day and finally got to skate them today. I know a couple people (Gay Imp Sausage Metal and Buttfart Rapedick) had posted some thoughts already, but here are my two cents after about an hour:
For reference, I usually skate 99 F4s, 51-53mm (currently 52mm conical fulls). I set these up on a pretty normal setup for me, a DOA 8.5" flat with Ace 44s and no risers. I was worried about ghost pop from going up so much, but these actually felt really nice with the mellow kicks.
As far as the wheels themselves go, they're really nice. I get the F4 comparison for sure, but these feel smoother and the slide has a lot less bark. Still just as fast, though, and just as easy to break into a slide. And even though they're technically a harder durometer, they dodn't feel more glassy or anything like that. One thing that is super cool is that they seem to roll through weelbite really easily, and even when I could really feel it I didn't get pitched.
As other have mentioned, these have bubbles and cosmetic flaws. And yeah, you could seriously rub the graphic off with a paper towel. I am into that though, as it adds to their charm.
I am going to stick with these for now. They're different from F4s but they still have many of the characteristics that I like and they feel even better on shitty, crusty ground. I'll report back as they go.
Edit: I feel like I might have to take the spitfire sticker off this board though.