Yes I agree, there was a time where it was worse and FF just did not have the same support coverage for Browser APIs etc, but now if I encounter a problem in FF I tend toward blaming the website developer for ensuring it works ok.
Thank you for the inspiration from your nice and simple real-time API. I made a pass a few years ago on digesting similar GTFS data and you've made me realise how much simpler it could be! :-)