So based on this thread bus service at the value resorts is either "horrible" or "the best" and at the Poly it either stinks or works just fine, etc, etc.!
I think the best thing to realize about the buses at WDW is "your mileage may vary." You simply can't generalize from your personal experience, whether it was good or bad. And one truly awful experience (like the bus driver getting lost! - yikes!) can color how you feel about everything else, even if it was mostly OK.
After reading posts over and over about how awful POR bus service was, we had a terrific experience when we were there 2 weeks ago. But I am sure that there were people at the same resort at the very same time whose experience was very different.
It would be great if Disney would add more buses (might happen), or train people better (I'm sure turnover is high, but they could work to overcome that), or use technology more effectively (they're trying, but the jury is out on its effectiveness), but ultimately I don't think it will ever work much better than any decent public transportation system. Disney certainly works better than Philly public transportation!
Free Disney transportation will be work well for you or not based on many different factors - your resort is only one of them. What park you are going to on what day, what time of day you are traveling, etc. will all impact your waiting time and the crowds you will encounter. Some aspects of your experience are completely outside Disney's control, like your own personal tolerance for waiting around, and sharing space with a lot of other sweaty strangers!
We have never been more than slightly inconvenienced by relying on Disney's transportation. However, I also know from reading these boards that there have been some real bus "horror stories"! Given how often we go to Disney, I'm sure that we will eventually have one of these ourselves. If I decide that I am unwilling to risk being inconvenienced or having a true transportation disaster, than I will start renting a car for my visits.
But I will try to refrain from generalizing and saying that "POR buses are great" or "the transportation from POP stinks", and simply report MY experiences so that others can make up their mind about what works for THEM.