I don't know how many years exactly but I know I bought at the peak of the pricing so it must have been early. Zero issues with mine.
The screen is great, bad experiences with Waldorf (Blofeld, an XT that was so heavily used before I got it I can't really blame Waldorf for wonky encoders) make me treat it a little gingerly when twisting the endless encoders but it's not really necessary.
The oddities (processing power, how modulation works vs. a modern mod matrix implementation) are key elements of the synth, no MK2 needed.