Long time lurker and first time poster around here -
Throughout most of the lounge threads over the years I've seen very few references to the YQR MLL (understandably so), but I had a very positive experience. The lone employee noticed two of us sitting near the door early in the morning and came to talk to us and let us in at 430 instead of 5 when the lounge regularly would open up. Extremely friendly and a more than reasonable selection of cold foods/breakfast that early and only for about 5 pax in total that morning.
As others have mentioned there is extremely limited seating/space (15-20 seats in total) but with the limited number of departures daily and few J seats and likely few status holders flying out of YQR, I doubt it almost ever gets too busy despite the constraints. The quiet space to sit and work made it a more pleasant experience than somewhere like the YVR TB and Dom later in the morning that seem to end up so busy so frequently.