I have a piece out today about how improving bus service is generally the low-hanging fruit of the transit improvement world, rather than things like mixed-traffic streetcars that look cool but offer few transportation benefits.
Something I've heard a lot in response is that people worry about "BRT creep." And they are right to worry! The way this works is that you start out by saying that this really great bus system will be way cheaper than a light rail line with a dedicated right-of-way, and then once the light rail proposal is dead you build a really crappy bus instead. That's terrible! But I don't think you should see that as a problem with buses, it's a problem with cheapskates. If you look at the H Street streetcar line in DC where we're spending a lot of money for little transportation benefit, the way I would frame it isn't that we spent too much money but that given the money we spent we got far too little transportation improvement. A similar amount of money spent on basically the same kind of project (improve the H Street Corridor's connection to downtown) could have accomplished a lot more had it been more focused on improving transportation in concrete ways and less on ribbon-cuttings and symbolism.