Bobby, we sold the Vertical SBX for a while and had great results with it. Unfortunately, it too has been discontinued and replaced with their Summit 80 and 800 systems, reasonable replacements for the STSe and XTS. None of the components are compatible, but the phones are, so your STSe or XTS customers can use their phones on these systems without limitation. There is a certification process in order to sell the Summit, but it's on-line and at no cost, and your dog could pass it.
Programming is similar to the XTS, has a nice web browser-based programming tool (no laptop software required), and of course, programming through a phone. IP remote phone support and networking are strong as well.