I really realised how lucky we are when our line was closed for engineering work at few weekends ago. If I went to Catford or Crofton Park…they only have one provider. We are so lucky to have the Overground when Southern let’s us down! If you want to have a giggle and look and some funny commuter photo’s - check this out!
I agree in that we are quite lucky in that we have a more frequent train service than many other stations in South London. How much of that is to do with two providers I’m not sure though. When the lines are closed during weekends, usually none of them actually run any trains, instead we get a rather unreliable and poorly advertised replacement bus.
I also generally feel let down more by the Overground which is often far too busy to get on, very uncomfortable to travel on, very slow in general, and also gets very crowded at Canada Water station. While Southern trains can get cancelled occasionally (though a much rarer event these days), I always get a seat on my commute and mostly one that is actually comfortable to sit on. This really is a rare exception for other commutes from Zone 3 in London and I have a lot of jealous colleagues at work some of which have to stand all the way from Haywards Heath!
Just to be pedantic as well, Catford and technically also Crofton Park have two providers too, Thameslink and Southeastern. Not sure I would want to swap though, although I do find Crofton Park a useful alternative depending on where I need to go.
At least HOP station is pleasant to stand around on! Crofton Park station is filthy & before anyone comments, I have been to a Cinderella meeting & complained! They are supposed to be spending money on the station & there have been some improvements, but on the whole it’s still pretty dismal 
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