Actually, I've used Monotron to process my Novation KS and guitar in one of my recent tracks (you may here it here: http://dommusic2.bandcamp.com/track/dow-dca-wiatru
, in the second part of the song). It was little noisy (actually more than little), but I've managed to use noise reduction from my recording software without much tone loss, rest disappeared in mix. Frankly speaking, I've used noisier gear in my life.
Casio CZ-1, Elektronika EM-25, Yamaha TX81Z, Roland JV-2080, Novation KS-rack, Korg Poly 800, Casio SK-1, Casio SK-8, Vermona E-piano, Akai S2000, Roland SP 404, Roland TR 505, Yamaha MR 10, Yamaha RX 21 and more