ControlNet is rock solid and easy. The only problems I have encountered were on some very eary versions of firmware and RSNetworx about 5 or more years ago, and even then it was really just a case of following the directions carefully.
Rules:
Buy the correct coax (1786-RG6), all the correct 1786 components and buy the recommended Crimp and Termination ToolKit (1786-CTK). Standard TV RG6 coax is not good enough as it is not quad-shielded and tends to be too lossy.
Ensure you follow the simple, but essential trunk length/#droppers trade-off rules.
Like Devicenet, 85% of network problems will be traced to poor or faulty hardware technique.
Use the latest version of RSNetworx that is fully compatible with the firmware matrix of all the CNet adaptors.
Understand exactly what the NUT, RPI are and how to choose values that make the most sense for your application. Usually Rack Optimisation will be more than adequate for most Remote I/O chassis. Put any 1756-DNB's in the local chassis, otherwise they gobble up lots of bandwidth.
Set SMax and UMax to sensible values for your network. ControlNet gives the engineer quite a lot of freedom as to how they will weight the various bandwidth trade-offs to get the result best suited for the application, but overall you'll find that it has a LOT of capacity that can be stretched in a number of very useful ways. Normally you run into the connection limits of the 1756-DNB's before you run out of CNet bandwidth.
Have a look around on the KnowledgeBase site, I'm sure you'll find a document describing all this and more.