Using part of it fairly regularly, I find the Rhein-Ruhr system fascinating. Some could say that the polycentric nature of the region is an advantage from the transport point of view, as the loadings are not as heavily asymmetrical as London's. That seems to work for Germany's inter-city network, as the whole country is a lot more polycentric than GB. There are plenty of fast services between the main cities in the region. The problem is that the fares vary depending on the train. You can pay top whack for an ICE, middle-whack for an IC or bottom whack for RE, RB and S-Bahn. The latter fares are very attractive because they also include local transport at each end, whereas the DB fares for shortish routes do not. And for my journeys from Flughafen Duesseldorf, even with ICE/IC I would generally have to do the Duesseldorf end of the journeys on a slower mode, but still pay the top prices! For me it's super annoying that the best value trains for my journey, RE1 and RE5, have this 20/40 min split every hour. If they just prised another path in so that they could be at regular 20 min intervals, I would be a contented bunny!