the tools they have for accross the network aren't terrific.
For a great free tool for pc to pc (this gives you more information than you could ever want, including the software license keys installed on the machine, and it's 100% legitimate)
For network management and info, I love this program (also free).
This program does require the computers you want to inventory to have SNMP turned on. It will also detect, printers, routers, voip devices, mapped drives, scanners, fax machines, servers, and many other miscellaneous networking equipment. It also allows you to submit support tickets, and allow your customers to do the same thing. Really too much to describe here.