Seriously, this. Even BB Madison is a very generous cut. @gettoasty doesn't know what he's talking about.
Spier & Mackay makes some nice OCBD's in terms of fabrics/collars and a good price point, but their fits actually are all too slim. For reference:
S&M's most generous shirt cut is their "contemporary." My size in contemporary, 16.5, has a 46.5 chest measurement; that's pretty darn slim. For comparison, Lands' End tailored fit dress shirts in size 16.5 have a 49.5" chest. That's their tailored fit, and it's a full 3 inches larger in the chest than S&M's most relaxed fit. Brooks Bros' "Regent" or "trim fit" as they now call it (their second slimmest out of 4 fits) size 16.5 has a chest measurement of 50.5".
I wish S&M would make an "athletic" fit OCBD, or something, with more room in the chest and shoulders.
I'm a big Spier and Mackay fan, and browse this thread for collar roll inspiration for my custom OCBDs from S&M.
I'd point out that their custom oxfords run around $100 CAD (and less when purchasing 3+ or on occasional sale). You can customize collar details like interlining, shirring, etc.
You can even send in a shirt that fits well and they'll generate your measurments from that.