I have a Jobo color processor and I'm very happy with it. If I want to heat faster, I can boil hot water and mix it with the cooler water and bring the water bath up very quickly.

If I want it to be really fast, I can heat hot water with my coffee maker, or heat the cold water in microwave.

But I never over-heat chemicals. The color chemicals are toxic... No microwave at all! The fume can kill you!