It's very accurate now. I don't know when your experience with it was.

It pulls from the same source that Google Maps currently does, so feel free to use whichever you prefer.

I last used it about 4 or so years ago, so of course things may have changed. It was appallingly bad though, to the point where it was no more accurate than posted schedules on the routes I rode. I just quit using it because it was so thoroughly useless. The sad thing is that it previously had worked extremely well. Glad to hear they've fixed the issues.