As a young professional working in TO who's semi-knowledgeable about menswear and takes care in his presentation/style, I'm a big fan of Suitsupply.
The 1st suit I bought from them was during summer '14 - loved the style (light grey/brown suit with a silk/linen blend) and the tailoring was impeccable after John fitted the suit. Unfortunately, it had the same problem as a previous commenter, where the pants' inner thighs frayed after fairly light wear (1-2x per week at the office for less than 3 months). I brought the suit back in and wanted to replace the pants - however, after a few weeks of correspondence with their sourcing group, we realized the fabric was already sold out (Fall collection was in effect). To my pleasant surprise, the store manager offered to take back the suit and credit its full value (including alteration cost) for my next purchase, which I didn't make until this summer! If that's not outstanding customer service, then I don't know what is.
Since then, I've also a bought pair of trousers & shoes from them, both of which are now part of my staple office wardrobe. Will be coming back again soon.