Beersmith
What do you like about the program you use?
It does all of the calculating for me, which is nice.
What is it missing?
It has a few quirks that annoy me sometime. Like when I want to add 3 ounces of malt, and the measurement is by the pound, I have to figure out what 3oz. is in points of a pound. The delete button on the keyboard also does not delete ingredients from a recipe, which I think it should (instead, the delete button on the program has to be pressed). Finally, the inventory management system is a little wonky, but I don't use it, so it doesn't bother me.
What does it do really well?
Calculates all of the "stats" of my recipes very accurately.
Why did you go for the one you did?
Tried it, liked it. The annoyances are small, and I'm sure will be addressed in future versions. Wish it was an open source project, I'd contribute heavily to it I'm sure.