That's strange....... I had a 34min flight time to LGW the other day. Don't think the jet does it much quicker - and if it does it'll only be by a minute or two - which makes not much difference to pax when we had them in 15mins early anyway...
Nothing to do with performance, but the 400 is much nicer and brighter inside.
And having flown goodness how many pax over the past 18months on the 400, I've heard not one complaint about the noise or vibration, although maybe I have had the odd one about a nice 'hard' landing!