I recently tried on a 38R fitz and regent. No question the fitz was slimmer in the jacket (especially shoulders) and the pants. However, the regent had a tighter fit in the waist, because it was a 31, but below that the pants seemed baggy like you would expect from traditional BB. I didn't find the regent to be "slim" at all.
Good to know, thanks! Considering that BB describes the Regent as `a contemporary take on the classic Brooks Brothers suit... Updated with slimmer lines, a narrower lapel with pickstitch detail and trimmer trousers, I would have thought that it was indeed a trimmer suit in that the jacket had less allowance than a more traditional suit and the pants were actually slimmer as well. From what you've posted, seems like the Regent has an normal/average fit with a 7'' drop instead of 6'', hardly what I'd consider slimmer.