Was tempted by the Rovacom when I was looking at adding more modules to my (Then) Rovacomlite. As the Rovacom does not have the BECM CPU software module, I decided to buy the complete set of modules for the P38. After many years of good use out of my Rovacomlite, it decided to give up the ghost I have now replaced it with the Faultmate Extreme which is certainly an impressive piece of kit and seems to be more stable than the old RCL.
Many people have tried to find alternatives to Test Book and failed. Except that is BBS and Autologic. I worked for Hewlett Packard until my retirement and they manufactured the Test Book, believe me, I tried to discover the workings of the system with highly qualified Systems Engineers at HP without success.