This is a decent Starbucks. Not the best, in terms of ambiance, but definitely nowhere near the worst.
It's on a corner of a busy street, just down the hill from the cathedral. The cafe itself is pretty small - probably half a dozen tables or so on the inside. It was busy when we were there, but not full. I saw several students with laptops. There were also half a dozen tables with umbrellas outside, which was very nice, but it wasn't the greatest patio space ever, because it was on a busy corner that had plenty of cars and people going by, but not much atmosphere (the cafe across the street, with a much more spacious terrace and a fountain, seemed to be where all the atmosphere was at).
However, my sister and I were dying for some refreshing iced coffees, something that was harder to find in Montreal than I expected. From my trip there, I noticed a lot more Parisian-style cafes and bistros, as opposed to American-style coffee shops. And sometimes, you just want to grab a cold coffee from the counter and sit outside with it.
The girl who took my order was super friendly, in a nice way. I had a free drink coupon, which I was happy to find I could use in Canada.
There were two bathrooms at the back that were in good condition, as well.
I had some trouble with the free wifi. I had my iPhone with me (AT&T data turned off), and when I tried to connect to the free Bell wifi, I kept receiving error messages in Safari instead of landing pages. Other people had their computers and phones, so if I'd inquired, I might have been able to get some help, but I wasn't that interested in using it, so I didn't bother. I was intrigued by the issue, though.