I’m sure there will be certain settings here and there that can sound alike… but overall, no.

The prophet 6 & now ob-6 are just the type of instruments that no matter what you dial in, it’s going to sound good. I’m not sure if the same can be said of the Analog Four/Keys … I frequently see people saying you have to find the analog four/keys ‘sweet spots’ to those who are unhappy with its sound overall.

this is of course reflected in the price differences between the instruments.

ymmv.

btw, if I had the money I’d go with the ob-6 over the prophet 6 - just personal taste, as you can’t possibly go wrong with either.