If you've been doing internet research on amps, that probably means that you've read way too many "initial impressions" posts on the huge difference that some fancy amp made in some guy's system, and have found yourself in a frustrating situation where you are trying to buy the one that sounds the best, but can't be sure which person to trust. Here's my personal experience, out of having listened to a bunch of different amps: I can't hear the difference between any of them. I don't think you will be able to either.
So my advice will be to get the idea of "which sounds better" completely out of your head. They all sound the same. Power (more is better), build quality, and looks are what you need to decide on. Yeah, looks don't influence sound either, but honestly, that's probably what's behind all those impressions posts you've been reading. Don't believe me? Notice that the guy above me just recommended a McIntosh! Worse specs than class D, no audible difference, but it looks pretty cool sitting there. That stuff matters. If it didn't, we wouldn't have discussions about sighted bias.
Anyway, between the 3 you listed, Purifi is the "best" choice. But again, you're not going to be able to hear a difference between that one and one of the Apollon $1k Purifi amps that are also available.