Biggin is actually a nice place to fly. You won't generally be waiting in a queue but there will be insanely busy times (usually in the afternoon). Jet traffic does get priority but you won't be told to orbit to "let something else join", most jet traffic will fly straight in on the ILS. You certainly won't ever be told to go around for the benefit of a departing jet. You may find you are told to land and return to the hold for jet arrivals or if there is someone flying circuits in a jet - which isn't very likely - before being able to continue.
The benefits are a HUGE tarmac runway, self-service refuelling (no more bowser chasing!), ATC, and... oh yeah... all that jet traffic (as it will be good experience for you to mix with commercial traffic, in case you actually want to fly somewhere, particularly abroad where English speaking airports tend to be the bigger ones!).
The biggest down side, other than the place being on a hill and therefore a bit closer to the clouds, is the cost of flying there. 10 landings cost over £200! 10 circuits over £70.
You get what you pay for though... did I mention the HUGE runway?
I'm sure Biggin is a lovely place to fly. I may have had the details wrong but training at an airport of that sort you will, on a regular basis, be asked to sit doing nothing on the ground (paying flying rates) whilst the tower prioritizes an aircraft that those who run the business consider more important.
And landing fees? Crikey. Not even included in the flying costs? That's going to seriously add up if you find you need a few hours of circuits to master the flare!
Most smaller airfields have self-service fuel don't they?
Don't know if a huge tarmac runway is a training benefit? How will those who trained that way manage when they come to land on a 500m bumpy grass strip? If you want a huge runway with a cheap landing fee and no traffic anywhere to be seen, go to Manston ;-)