ATRs problem with bags is mostly on short routes, SJU-STT, or POS-TOB. Max TO weight is 1500lbs difference, so you need about a 1 hour flight to burn that to be able to TO at max weight and land at max weight. Our -500 are a little better, and I imagen that your -600's have better performance too. I do like the cargo in the front and back of the ATR. It's easier for weight and balance to plan the cargo loading so you don't need to move the passengers around too much. The Q400 seems to be a good machine but I don't know too much about it's performance numbers. I know it's fast, but on a short route like POS-TOB I don't think their is much difference. Our ATR's carry about 5000lbs of cargo with 64 passengers. The cargo compartments are really big. I've carried surfboards and car parts all the time and they fit fine in the front cargo hold.