I was one of the people who long ago bought a RomScanner. For game switching, it seemed to work as promised. It was nice to have 10 games at your fingertips.
HOWEVER...
The actual physical design was a nightmare. It seemed to be designed for single controller type games on 6-switch 2600s because it'd block the difficulty switches and you'd have to reach around the legs to get to the controller ports. And speaking of the legs.. that was the absolute WORST part of the device. The legs were "secured" into the main device by putting the round T-shaped pegs on the legs into holes on the bottom of the (once loaded w/ cartridges, quite heavy) device and sliding them into place. Included were velcro pads to help secure the device to the 2600. It seems as though they never tested it with a full load, because the pegs snapped off VERY easily. We returned 3 of these before we gave up and went the superglue route to fixing it.
I don't remember what happened to it though.. it was probably in with my original 2600 (with just over 100 games) that I gave my nephew, which ended up at a Park & Swap in Hawaii somewhere. (Along with the Intellivision 2 & 30 games and the Genesis w/ language switch)