NES Classic is absurdly overpriced, uses a Raspberry Pi, a proprietary and bad controller (the controller is the same one that the Wii Classic Controller does... with a two foot wire -_-), and no possibility of new games.
If I'm going to be emulating anyway, a Famiclone or something is the way to go. Doesn't really seem to be much better than the RetroFreak. Want to play backups? You can. ROMs? You can, but I'm not endorsing it. Real carts? You can.
You can even dump your real carts, although I think it's a proprietary dump that only the RetroFreak can read. PC emulators don't recognize them as valid ROMs. Handy if you, you know, don't wanna keep the cart in all day.