The user interface of H&C's Revit API plugin was very easy to use. It saved us tons of time in creating complex models for our clients' buildings. Also, they are always there when you need them! We used their service every two weeks for our projects, which made it easier than managing an internal team. At first I had some concerns with regard to how reliable their implementation skills were - but after working with them for over a year now we have seen that they are more than up to speed. Sometimes it would be nice if H&C could provide additional documentation or tutorials for other users who might not have as much experience using Revit. For example, I found most of my workflows through trial-and-error. Having a set process laid out by someone else really helped me understand what each step should look like.