I love my RH Designs timer. It's great!
At one time, I had a Zone VI compensating developing timer. It was the worst piece of darkroom equipment I've ever had. It had to be fixed 4 times, and of course it took awhile for me to figure out that it was broken! So I'm happy that RH Designs is going to build a better one, right?
One thing to remember is that at certain temperatures some developing agents simply stop working. Will this have some kind of warning? Will it say what the actual temp is?
Regarding use in a Jobo, the temp of the water bath is always a bit higher than the temp in the tanks.
Does all film respond to temp changes in the same way? I would expect that a 10% change in temp for TMX would make a bigger difference that a 10% change with Tri-x.
Anyway, just some things to consider.