I have used Ossolution Team's products and they always work right out of the box. When I did have a minor complication after moving to a newer server Tuan (my support guy) was very responsive and alway eager to assist me in getting the issue resolved quickly and accurately.
Help Desk Pro is the third and last ticket in system I'll use. It has all the features my small business needs and my client have no problems submitting support tickets to me.
I am VERY happy with this mod.