I have one (somewhere) but I really didn't use it for very long. It's not a bad device, and the emulation is better than most, but the lack of options ultimately had me go back to the Raspberry Pi and then the FPGA solutions later. The main thing I got it for was so I could play SNES on the HDTV without a scaler, and it played them fine but it wouldn't write the save back to the original cart. It's really more of a cartridge dumper than a system that plays carts in real time. If you're industrious you could use a Retrode with your Mister and do the same thing.
On the plus side, the best thing about the device was the controller converter it came with. The included SNES clone controller was ass, but the converter to use real SNES, Genesis, or PCE pads was awesome.