If you can afford a better tstat get one. Those are not digital and can be hard to dial in and have a reputation of breaking. Your tstat is the most important thing you can buy so buy the best you can.
I live these.
http://www.spyderrobotics.com/home/products.html
I have s Herpstat 1 & 4 and they are awesome. I have had the one your looking at and a hydrofarm, both broke in a few months.
While you can run two uth on one tstat I would NEVER do it with the one your looking at. When it breaks the second will mean you spent the same as doing it right the first time with a good tstat.