Hi Aine,
You will find that Betfair live video is usually the most reliable and quickest option. Viewing it through a web browser such as Chrome is advised though. Ocassionally they change their system that means third party viewers have streaming problems (its like adding another layer).
In comparission to Bet365 and the like you will find they are all using the same live streaming service, there is just varying differences between viewing criteria. For example, on Betfair exchange you may have to place a bet to watch. On others you may not.
Some of the smalelr providers will not have every feed or stream though. The two you mention will both be okay I should think. I have seen slightly longer delays on B365 in Tennis. For specific sports I don’t know. As grant9 suggests there, it could change depending on event/sport/time day/browser etc.
Kind Regards
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