Don't believe what easyJet and Ryanair tell you on their websites about on-time performance, they are very selective about what they choose to analyse.
Check out the official CAA stats at
flightontime.info for a more accurate, comparable picture.
Ryanair are in fact very punctual compared with most to date this year, but they are not the best.
Funny to see BA and bmi performing worse than the low costs though!