The arcade I go to just got this, and while I can't speak for everyone, most everyone who got a chance to play it (including myself) thought it was absolutely amazing.
The new songs are fantastic (I love Fallen Angel so much) and the charts for them have stopped being ITG charts ported to pump and now they play like a mix of the stamina and speed difficulty that itg brings and the crossovers and sort of flow the charts have for pump. I feel like I don't want to even go back to the old charts, just play infinity charts forever haha. Oh and the new routine charts (except for fresh) are absolutely amazing, and they brought back a ton of the pro routine charts (which were the main reason I played that game)
Also a ton of amazing additions to the game mechanics, you can now choose between pro mode, which works like ITG with a fantastic timing and stage break on, and classic mode, which has no stage break at all (The choice to have this on is just so so great) and only up to perfect timing. There's also a percentage counter just like in itg so you can glance at it to see how your doing, which is very much welcome. You can do the hallway mod, and all of the other perspective mods as well, and there's a noteskin called rhythm that has the blue red yellow color change for types of notes. Besides that, I'm pretty sure (though not totally sure) that custom charts are as easy to make and put in as they were for pro again, so hopefully I'll be seeing more great stuff like the routine for tension very soon.
Here's that routine by the way if you haven't seen it.
So yeah personally I think it's fantastic, it injects a whole bunch of amazing new variety into the pump series but still lets you play it like all the classic pumps if you want to too.