Reader t sent this article in about a Cleveland BRT-type system.
I've got nothing against BRT, and it certainly has the potential to have some of the benefits of rail at less cost, but the problem with BRT in practice is that there are always ways of doing it cheaper. So you start with the light rail line plan. That's too expensive. So, ok, you consider a full BRT plan with fully dedicated lanes, signal priority, etc. But then some politically connected people start complaining about the loss of a lane for automobiles in their neighborhood. Suddenly...you don't have dedicated lanes throughout the route. And, then, well, those electronic arrival signs get the axe due to more budget concerns. The point is, it's really easy to go from "cheaper version of light rail" to "just another bus system" as the process goes on.
