I suggest you take a look at SMS Pro out of Alaska. They've been around for years and started their software from a clean sheet made expressly for aviation. Their program has a clean look, is relatively fast (note my location) and their top of the line version has 50+ modules. That covers just about all the needs you'd have to keep you SMS under control. Price depends on how many modules you need and how many employees you have.
SMS Pro works and service from their programmers is very fast and helpful.