First, I’ll say that I’ve never personally dealt with Jos. A. Bank, so all I’ve heard is second hand. You could search through Styleforum and see the opinions others have of their suits, which generally tend to be negative. However, a few positive things have been said about their more expensive line — although there’s some consensus that while the quality’s decent at that higher end, you could take that same money and spend it elsewhere on something a bit better.
From what I’ve seen of their cuts, they do seem a bit wider and more boxy than perhaps most people would want — although I’d assume they’re catering toward men who hate shopping and just “need a few suits” at a cheap price.
Granted, you can buy cheap suits and have them altered to fit you and look decent (which I’ve done), but if you’re willing to put in the time and effort, then you can definitely find something at a comparable price but of higher quality if you know your measurements.
My main problem with shopping in men’s stores like JAB and Men’s Warehouse is the sales staff. Often, I think they’re misleading and pushy, which I do not enjoy. Any time my shopping experience starts feeling like a psychological tug-of-war, I tend to walk away or become unpleasant.
ADDING: From thisfits who brought to my attention Put This On’s thoughts on JAB.