I'm quite a fan of EZY.. have flown with them lots, and had nothing but excellent service every time. The one time I missed check-in, they put me straight on the next flight.. none of those shenanigans you see on 'Airline'!

[Have those stupid customers never heard of loadsheets/fuel/V1 calculations???!!!]
However, I simply DESPISE the free range seating system. The argy-bargy at the check-in, and again at the gate.. you turn into a paranoid monster when you think someone with ticket 145 is sneaking into the 1-30 queue!
When EZY merged with GO, they did some trials of observing how fast pax made it to the gate and how fast they boarded on each of the two systems - seat numbers and free range. The inevitable conclusion was that the free for all resulted in a faster board, and helped with EZY's tight turnarounds.
However, I think the most important thing EZY have done is create the competitive short-haul environment in the UK. I was a frequent flyer on EZY on the INV-LUT/LGW route and over recent years BA's ticket prices have tumbled in order to compete, and now it's usually worth checking BA's prices if you are booking far in advance, as they may be cheaper than LCCs...