I've used one and don't really see the point. They're alright emulators, but that's it, you're still playing a ROM, just one it rips itself, so I'd rather just download some ROMs on the internet and use the HDMI out from my laptop since they're better emulators.
If you can get the original hardware, awesome. Even better if you have a CRT TV to use with it. But unless you already own a lot of original carts, I don't see much point with the Retrons.
Now if you do go the PC emulator route, a wireless SNES controller I do see the point in.