London Cannon Street station is one of the main stations that I use to get to and from work. It's one of the main stations in central London and is the biggest railway station in the City of London or the financial district.
The only reason that it is one of the main railway stations in central London is because of where it is located - the next mainline station is a good 30 minute walk away. To be quite honest the actual station is pretty terrible for such a busy one and I only use it because it is the closest station to my work. If I had the choice I wouldn't use Cannon Street at all.
South Eastern is the only train line that runs to and from Cannon Street which means that it only transports people to and from Kent, East Sussex and the general South East of England. This means that when the train stops at London Bridge station, the train always gets completely packed with commuters needing to get to and from Cannon Street from everywhere else around London.
The actual station is absolutely rubbish with not a single shop or even a small sweet stand that you can pick up a drink or bar of chocolate from and it's not like there's loads of shops outside the station because the area is mainly made up of businesses. The only things in the station are literally the 7 platforms.
Despite the station always being packed with workers, the service isn't too great either. Almost every single morning my train to Cannon Street is delayed whether that's by only a couple of minutes or by up to 30 minutes. I don't think I've had an on time train in the last 3 months at least! Getting home from work is also a pain as the trains are often delayed or cancelled and my train has even been cancelled when I'm sitting on it with only a couple of minutes to go before departure! The only good thing about going home from here is that a lot of trains stop at London Bridge where there are plenty of more frequent trains running from and to many more destinations.
The digital train timetables are also pretty useless here as you can only view these in the main entrance to the station and not up by the platforms. There isn't a clock by the timetables so you can't even see what the time is when you're looking for train times - a very sneaky purposeful move I think so that you don't know how delayed they've made you!
The station is mainly aimed at workers because of its location and because the station is closed on Sundays.
Overall, a rubbish station that I only use out of necessity.