Yes, they are using SPx now. They switched back after last weekend when they lost some sales calls that were put in orbit and no one realized they were still there. The potential customers called back quite angry after being on hold for several minutes.
The SPx do seem to work a bit better now but they are still running into an occasional issue where the sales guys end up talking to each other on a SPx line and/or a sales guy presses the SP key multiple times in haste and loses the call altogether. This happens much less often largely due to the staff becoming accustomed to how it works. However management is dissatisfied with the whole setup.
I'm strongly pushing them towards a call queue setup but they are resistant because they had a Toshiba analog PBX for 15+ years and have always had sales calls handled in the same fashion.