I have ProMash and have used it for many years. I also recently tried Beersmith and BTP. I wasn't thrilled with either. They both have pluses and minuses but I like Promash.
My only quibble is that it doesn't allow you to price your inventory and give you a batch cost.
What I do like is having separate brewing sessions. I'll sometimes have to make a minor change in a recipe for a particular brew day and it won't affect my master recipe at all. Also, being able to go back and look to see how often you've made a certain recipe and when and read tasting notes, etc. is a great thing. The interface is a little dated but easy enough to understand.