I have all three f the big ones, BTP, Promash and Beersmith. I personally use BTP, but would rather have either of the other ones rather than my old spread sheet.
BTP is constantly being updated (for free) and includes practically every beer ingredient you can think of. you can always add ingredients to either free programs and spreadsheets, but the idea of me adding all the tedious things was ridiculous to me. I would much rather pay someone else to do that stuff while I brew beer.
truth is though, to each his own!