I'll look to J. Crew next.
I just picked up a Reiss summer suit today, and I was shocked at how good it is for the money (they were having a 70% off sale, which certainly didn't hurt). I'm a trim, lanky man (6'1", 160 lb, ~38.5" chest and ~32" waist), and the Reiss slim cut 38 fit me very close to perfectly off the rack. Certainly close enough to wear without tailoring. One of the sleeves will have to be shortened from the shoulder, and the waist needs to come in ever so slightly, but even though Reiss doesn't sell long-cut jackets, I found theirs was just long enough to work (it just covers the buttocks on me, though it would be more conservative if it were a half inch longer).
I was on the fence about buying from Suit Supply, and I"m pretty glad I didn't. Suit Supply definitely uses a somewhat higher quality of fabric, but that's at the cost of the structure of the suit. They say the almost complete lack of padding at the shoulders (some of their models have more padding, but it's clunky) is some kind of sartorial detail, but "natural shoulders" is code for "pad stitching is difficult and we don't want to pay for it." As far as I'm concerned, a suit is supposed to be a comfortable, versatile piece of armor. It needs well-constructed padding or it's not going to sit right.
Additionally, I loathe Suit Supply's overlapping cuff buttons. Fortunately the Reiss buttons just barely touch, which for me is how it should be.