Not sure about the other brands out there, but I have the Scotoiler mounted on my bike. Not cheap but so simple and efficient. Once you have it set up and adjusted properly you only have to give your wheel the occasional wipe over with a rag and everything is clean and lubed.
Some people like em some people hate em, but I got sick of cleaning off that black goop they called chain wax, it's more like chain tar.
http://www.scottoiler.co.uk/
