I have not used the herpstat 2; although, I have used the herpstat and the herpstat pro.
The only problem with the herpstat is that it does not have a resettable fuse. So if you blow it, which I did, then you are out of luck. To replace the fuse you have to solder a new one in.
The herpstat pro, on the other hand, does have a resettable fuse, so you never have to worry about blowing it. It will just reset itself.
If the herpstat 2 has the resettable fuse then I am sure it is just as good as the pro model.
I also love the night drop on the herpstat pro.