The wife, my self and a coworker did our 90 day report today and decided to try this out. For me, as I live on Ramkhamhaeng it worked out beautifully. From the school to back home, less than an hour. The immigration officals took care of our paperwork in about 5 minutes. From the Big-C on Ram to the airport is about 130B and about 15 minutes.
The only bad side - no taxis to get back home. We waited probably 20 minutes for a taxi at the hotel. Next, we'll just have our taxi wait for us.
Telephone number is 02-131-1096, or 02-131-1097. Office hours are 08:30-16:30.