These little 1RU beasties are a total PITA to program but are capable of generating some cool 80s analog sounds like the Juno series. Not great for acid-house tweakin', but nice for when you want to get all Depeche Mode and throw down some thick subtractive leads but only have a DX7 and a midi controller. I've never had any reliability issues with this synthesizer and its been dropped a few times. If you can score one for under $200 its a great investment to integrate a little real analog into a software based turnkey setup like Fruity Loops...
I've owned it FOREVER and I'm used to patching it the tedious way or with software mostly. I can definitely get it to respond to a controller, it just takes a while to sync up and then I'm using the MIDI input for that controller, ugh
The rackmount MKS-50, along with it's Alpha Juno keyboard equivalents, was one of Roland's last analog synths. It's famous for creating the hoover/"mentasm" sound that's been used in electronic music since the early 90s. I also have the separate PG-300 controller, which adds lots of lovely sliders to the experience. Purchased from a Richmond, Virginia pawn shop in 1994.
@jimmarchi1 - There are other good, modern options to control your MKS-50 without having to find an actual PG-300. Behringer makes an inexpensive controller called the BGR2000, and you can get a custom Alpha Juno/MKS50 overlay and sys-ex file here: http://www.synthgraphics.com/Alpha-Juno-Programmer.html. You can be set for less than $200.