As a frequent recent passenger flying through Luton, these are my views:-
Rail access. Very good, but you may well get caught in huge queues of traffic en-route depending upon the time of your journey.
Road access. Depending upon time of day excellent to pathetic.
Car parks. I have only used the executive at £10 per day. Pot holled, not secure and you get drenched walking to the tinminal!
Check in. Loads of desks, might as well be underground, no natural light.
Secuity check area. Depending upon time of day the queues are either very short or huge.
Shopping area. Very good, bright and airy, plenty of choice.
Departure lounge. Depending upon time of day spacious or packed.
If it is raining you will get very wet walking to the plane unless a bus has been arranged.
The most serious problem in my view is the road access from/to the M1 and railway station. Massive queues will form during both rush hours. It has on occassions taken longer to reach the station than the lengh of my flight!
That said, nothing would deter me from flying. A little investment in the car park and access to the aircraft from the departure lounge would not go amiss and be most welcomed from a passenger perspective.
I look forward to flying easygovirginexpressdbaJet soon.