I've generally had good experiences with Enercalc. I find a bug once in a while, but the support team is very responsive. They always gets back to me within a day or 2 to let me know if they can replicate the bug and that it will be fixed in the next release, which usually comes out within a month or so.
I've been able to confirm their results almost always, and if I can't their support team is very good about explaining the process and how they came to their conclusions. There are some limitations (as others have mentioned), the one that comes to mind for me is that the concrete shear wall module doesn't calculate any special shear wall reinforcement requirements (which would be very nice to have, but certainly isn't a necessary feature).
I don't work for Enercalc. I've been using the software for 8+ years.