I got myself a Tetenal colour kit to see if I could 'do' it, really. I followed the instructions to the letter, keeping the temp stable wasn't as bad as I thought, and I was pleased with the results both at 38C and 30C, especially on 120 film. But then I lapsed a bit, as I shoot mostly black and white, and in the meantime the colour chems were getting older, and older... I suspect if I did a colour film now it would come out of a fashion, but there'd be degradation because of age.
I would like to try E-6 processing at some point, as I've always had a soft spot for slides. I think if I were to do colour full time, it'd be E-6. Retirement looms!