I have been using Service Centre 6 for over six months now and I have to say that I am very impressed with it.
I deal primarily with broadcasters and studios where a great deal of PC problems have the potential to be mission critical and I find the tools in the Service Centre kit are ideal for quickly diagnosing any hardware problems. Whether it's power supply, storage, peripheral, memory or motherboard there is a diagnostic tool in the bag to help you find the problem. Even when the OS is unstable or unreachable, you can boot to diagnostics with the media supplied, either USB or CD-ROM. Even if the USB drive fails there is a utility to generate a new one.
I never travel to a field service call now with out it.
Even though I have seen some of the kit's components, or similar for sale elsewhere, I like the fact that Service Centre 6 has all the bits you need in the on place and if you need support, patches or updates then you can get them all from the one place. The support is great. I had a problem with the PCI diagnostic card and they sent out a new one straight away.