Yeah man I know how you feel, when I was building a incubator I had a bunch of flexwatt questions, I called Rich and he answered them all. Guy is all about helping you out which is why I recommend him for flexxwat, racks and theromstats.
The Ranco is my recommendation, and that's just because I own 2 of them and have never had a problem. I've never used the Johnson's though. Rich over at RBI also breeds BPs. Since he most likely has used both you might want to ask him about which he prefers.