Southeastern Railway is currently owned by London & South Eastern Railway Limited, it operates routes on the Integrated Kent franchise by Govia, who in turn is owned by two rather big players in the UK transportation game including Go-Ahead (largest bus operator in London, Manchester and offering services in other cities) and Keolis (A truly worldwide company who operate buses in Sweden, trains in Boston, the Metro in Shanghai as well as services closer to home such as Manchester's Metrolink, the DLR in London and TFW Rail services.)
While the interior of my train wasn't overly impressive or modern, it was comfortable for a short journey of 10 minutes between Charring Cros and London Bridge which also goes via Waterloo East, this is a zone where you can use your Oyster meaning it can work out pretty cheap to travel in comparison to a normal ticket. This journey only came to £2.40, with a daily cap of £7.20 for all zone 1 and 2 services in the cap which includes national rail, tube, DLR and buses.
Trains seemed to operate efficiently and quickly with services every two minutes between these destinations and the train staff seemed friendly enough at both stations, although I didn't see a train staff member on board which could be down to it being a short journey.
The website is easy to use and explains the ticketing system including Oyster well. Southeastern has 73 stations in the Oyster PAYG area (the price varies between zones obviously between 1 and 9), which is one of the highest of any railway operating company and I presume is second after TFL Rail.
I would recommend going along their central London route between London Bridge and Charing Cross via Waterloo East just for the view, with trains every 2-3 minutes during the day (which didn't get busy outside of rush hour) and a journey lasting just under 8 minutes, it is worth it for some great views on the bridge crossing including Parliament, Big Ben and the London Eye. 3* read more