My experience with Guardian Radon Mitigation was a very positive one.
We were in the process of trying to purchase a home and during the inspection elevated Radon levels were found. I asked around to some of my trusted sources I was referred to Guardian. After speaking with Mary Anne I felt very comfortable that this was the correct company for us. She took care of all the details for me; setting up the time with the current home owners to get the estimate done, forwarding all the documents to everyone that needed them (realtors, lawyers, both sets of home owners), contacting me after we closed on the house to set up the appointment, and scheduling a third party company to come and do the retest after the system was installed. With everything else that was stressful with trying to close on the house, she was a huge help.
The install process went very smoothly. They were prompt and professional and explained the whole process to me as they went. They took the time to make sure the system was in a spot that was out of the way and looked as attractively as it could. After they were finished, they left the area cleaner than when they arrived.
I would definitely recommend using Guardian. If you do, a small tip that may help you out; Pay attention to what shirts Chris and Bob are wearing, unless they were standing next to each other, I was having a tough time keeping track of which one was which.