If your dingo was the 420, I can see why it only sold for less than the asking price of my bobcat. However, at $4k, unless it was complete junk, you sold it about $2k too cheap! Guaranteed I could get $6000 for 420 in good shape around here. Maybe the economy's still sour where you're at.
There's no comparison to that machine and a mt50. Yes, the mt50 is heavier but that's because it's not made of plastic like the 420. I was just really unimpressed with the 420 I owned. A 425 is a lot better. I might compare that machine to a mt50 but definitely not the 420.
MT50 is certainly not the best mini skid out there. If someone has $20k lying around, they should buy a sk650. If they only have $7k, then a bobcat mt50, dingo 425 or ditch witch 500 would all be good starter machines.