I recently pensioned off my Ensoniq SQ-1 for a PSR740. The SQ-1 was never totally reliable and even had a complete main PCB exchange a few years back which helped, but did not totally cure everything. I have now used the 740 many times for live performance and never once has it put a foot wrong. The Ensoniq would suddenly be out of tune or suddenly change its sequencer tempo or start making funny noises. I would have to agree with the 1st reply and say give it a miss. I am in the UK and the agency has changed hands several times, I am not sure who if anyone is supporting them now.
Paul