I have the M&W Traveller bag for almost 2 years and love it. It is heavier than the nylon bags, but looks great and is bulletproof. The ergonomics on it are also great. I travel for work 30+ weeks a year, so it gets used pretty hard.
I also have to commend the customer service. I tore the back flap (where you would tuck a magazine) almost off on the underside of an airline seat. I sent it back to them in Oklahoma. I expected to have to pay for this as it was clearly damage and not a defect at all, but they fixed it and shipped it for free in about a week and a half. They even conditioned it for me.
The only downside is the additional weight, but that's not a big deal for me as I usually have so much weight in the stuff packed in there (laptop, charger, notebooks, reading books,magazines, files, etc.) that it would be heavy regardless of the weight of the bag.