In terms of long haul, look at their on time performance from LGW the last two weeks. Many, many delays, with one I think even stretching to 48 hours and them not providing hotels for people - there's a long thread on airliners.net about their long haul 787 problems (actually quite an interesting read!)
In terms of short haul they seem to be doing well at Gatwick, but that's because the demand is there, it simply isn't at NCL