Over the last 20 years, I've had just about every rack piece they've put out including the midi controllers.
The single space units...ala Mach I and II, LT, Alpha, Power Plant and the like are pretty durable and functionally clean sounding. I always preferred the Rockman chorus over ART though. About my only complaint there.
The SGX2000 series was a monster when it came out. Naturally I HAD to have 1. At 700 bones, it was pricey but in 91.....it was the cats ass.
I've had 2 SGX2000s and a Nightbass. They all 3 had the crappy chorus but for studio work in the 90s, I couldn't complain. I wouldn't gig one without a good shock case though....and here's why:
The tube (yes, just 1) 12ax7a is mounted on the PC board which IMO was a dumbass move. Tubes generate heat...PCBs melt. The tube itself is mounted well with a retainer strap and or a shield. I've had both. I'm assuming the shield was to combat heat issues in later runs. There was no fan, most likely to not have any noise issues. The wiring from the power supplies on all 3 units I had looked like they were run by a 3rd grader and not soldered very well. 2 of them had wires separate from the PCB resulting in 2, 20 pound discotech looking paperweights. Easy fixes though.
For them being tube preamps...IMO, the gain structure swallows. Just not enough there. The effects loop saved the day on these for sure.
The X-11 controller is a good cheap unit. Easy to use and ya can park a truck on it.
The X-15 controller is way more usable but has issues with the expression pedals coming loose and sloppy feeling. The bank up/down buttons are too close to the 2nd EXP pedal. My only 2 complaints.
Good units for studio work if you can get past the grainy chorus. $200 on Evilbay isn't a bad price for 1 to play with, even better deal if it comes with a controller. So long as you stay away from modded units. Anyone on this board wouldn't have any problems programming one.
Only thing I would change is adding a couple more tubes to make the gain more usable.....but hey, thats what we have tube heads for