I've had one since 2005. I fumbled a bit with it until I got hold of a syllabus used in WoodRat training courses West of London. If you'll send me an email, I'll send you a .pdf file of the 43-page syllabus. It walks you through the basics.
It is, in my opinion, more balanced and understanding towards new users than the official manual. The latter can be downloaded from the WoodRat website.
As you suggested, is it expensive. But if you weigh its productivity against the Leigh Jigs, for about the same cost as the Leigh FMT (for Mortise/Tenons) and Leigh Dovetail Jig, the WoodRat will not only perform both functions, but these as well:
Comb (Finger) Joints, Tongue & Groove, Half Blind Dovetails, Angled M&T, Lap Joints, and a half dozen lesser used joints. This versatility, however presents more of a learning challenge though. Seldom mentioned are the gains. The dust collection is pretty good in most cases. The unit mounts on the wall, so it doesn't eat up valuable shop real estate. Safety is exceptional. You are never close to the cutters. And high up on the list of advantages is that you don't have boxes filled with fiddly bits to configure the machine for use. Partly because of this, the machine works quickly.
About 3 shop-made jigs really expand your woodworking repertoire, and they are virtually free. Scrap wood. I would highly recommend investing £5 to get the Introductory Video first. And send me an email to: [email protected]