As one who has flown both the ATP and 146 ( currently flying B777) I must say that both aircraft are good at what they do. From what I can gather BWA did have problems with the ATPs in Aberdeen but it must be said that it sems they were not getting the engineering support from HQ. Look at BRAL, they seem to be having good overall dispatch rates with theirs because they are well maintained. When it comes to the crunch I believe the ATP has the advantage over the 146 it its bad weather performance. I have flown both and know which I would rather be flying on a cold, windy winters evening in the Shetlands. That being said you can understand why the pax love the jet. But you have to look at the bigger picture and with good engineering support I believe the ATP is the aircraft for the job up their.
Anyway good luck to whoever gets it.