Which model of Herpstat do you suggest?

I ordered a 6 shelf rack from Animal Plastics, and I was just wondering which model of Herpstat (or another brand if you have any other suggestions) should I pick up for it? I was thinking about the Herpstat 2. My current thermostat is a cheap old thing and I want something better.

Herpstat 2 is good if you have plans for expansion (another rack). There's no point in getting anything more than an Intro or 1 for only one rack.

I have Herpstat 1 and 2, it all boiled down to your needs.

I have a herpstat 4. It is controlling a 3 tub adult BP rack, a split juvie rack (5 tubs, 2 on one temp and 3 on another), and the UTH under my male Bca's tub. I LOVE it.. But, the downside is that all of your equipment must be close together for it to run everything. (all of mine is along one wall). It ends up being cheaper per channel than buying 4, herpstat 1s, but it's a chunk of change to pay upfront.