£200 for a dx2? Blimey.. And they must be old by now too...
I used to have a pile of old snes copiers (super ufo/profighter/professor etc...) but sold them all. They were all unreliable imho - I used to fix them for friends - internally they tended to be very cheap; the voltage regulators always knackered (and was pretty dodgy to start with).
Best console backup unit I've ever seen was "Mr.Backup" or 'Z64' for the N64.