I've tried most of the big calendar apps out there, and have purchased a handful of scheduling LTD's over the years - and Trafft is hands-down the best one I've used (and definitely at the best price) :)

It has powerful functionality, even for solopreneurs such as myself -- and the developers are extremely responsive if/when you have any problems.

Where I really see Trafft shining, is for businesses with multiple employees - and who may even offer differing services. I have no use for this (yet), but I've run it through its course and client scheduling in multi-employee/multi-service environments is incredibly versatile and will be a boon for any small to medium-sized business.

In a nutshell, if you get Trafft, it should be the only scheduling software you'll need for now and the foreseeable future.