We had a great experience with 1-800-Rid-Of-It. We ended up having them come twice within the span of a week. Both times they arrived within the time window (about half an hour after the start of the window) and called me when they were on their way. The first time I had to send them back because the service elevator in my building had broken. Deborah, who manages the appointments, was super helpful and nice about it. She gave us lots of different times on short notice, and was very patient as we tried to figured out what would work for us given that this was all last minute.
The second time around things worked out perfectly. Kevin and Andrew, the moving crew, were great. They were nice and worked really fast. They started by giving us an estimate of somewhere in between a quarter and 1/3 of a truck, which was what we had been told by Deborah as the preliminary quote. We had been worried about moving out a large 9 foot couch, but it wasn't an issue at all and they even brought a saw to cut it apart if it was (it does cost extra if they actually have to use the saw). In the end, the junk took up a third of the truck, but they gave us a 10% discount because it was really easy to move.