I was living within a few miles of Doncaster Robin Hood Airport until recently, and having flown in and out as a pilot of a based light aircraft found the security and service excellent. The airport was an absolute pleasure to fly from.
For business, I prefered Humberside. Firstly because Humberside has the KLM flights, but secondly because its just such a cosy airport, everything is setup to make it easy to fly from there. You rock up 20 minutes before, and if the doors are still open they let you onboard. What more can you ask for?
If Doncaster was to take on a scheduled flight like the KLM one, it would have to offer a customer service, particularly to it's Gold and Platinum passengers. Fasttrack services, a good lounge, priority boarding and the ability to leave your carry on at the door and collect it on arrival AMS. My worst experiences at DSA have been with arriving and having to wait over an hour for a hire car because they don't have staff onsite despite booking the car in advance.
They seem to be setup to meet the low cost airline market, and as a business traveller it can be a bit of a nightmare mixing with the low cost holidaymakers, and after a couple of experiences I refuse to do it again (nothing snobbish, just life seems to be made difficult).