I used to live around the corner from this Metro (when it was a Dominion) and back then it wasn't very good. The place is pretty small for a grocery store but it's located in a very high traffic area. Right in the middle of the Annex, so basically every U of T student was here at 3:00am buying munchies and late-night study snacks.
I used to like the fact they had a Coinstar machine, even though it was right by the cashiers and was super loud and somewhat embarrassing. The place was so cramped that when lines got busy you would have to line-up down the aisles. So I was pretty surprised when I went there recently they seem to have narrowed the aisles and have made things even more compact.
I seem to remember my experiences there not being very good. Sometimes I would try to hit up other places on my way home from work to avoid shopping at the Walmer Metro/Dominion.