Ill throw in my 2 cents here
I HAVE BOTH
yes, i have a Herpstat, and a Hydrofarm on/off thermostat
I gotta say, they both work AMAZING.
the hydro farm is keeping my leopard gecko warm and happy at 95 - 97F, and my herpstat keeps my boa nice and warm at 89 - 91F.
They both work amazingly. if you cant afford a Herpstat, get the hydrofarm 100% I have had nothing but good experiences with it so far