While I think something like this makes sense, the pricing seems off. For $600 you can build a PC with a desktop GPU. If you want to make it easy to set up, you could just use an off the shelf mini-PC and preinstall everything so a non-technical user can get started without any hassle. I really hope we’ll see more Steam machine like devices in the future.
I haven’t had any problems here. From what I can tell, it just hands all the input and display off to your configured emulator of choice once you make the selection, so once you boot the game, it’s however you’ve got that emulator configured.
Maybe they’ve finally fixed those problems. In Lakka, I set my controller up once (for each unique controller) in RetroArch frontend, and then it works in any emulator core. I don’t think it’s normal to have to set up the controller in each core (but you can, if you want or need to!)