I've always thought most of their salmon was pretty sus. Lots of it looks like it's dyed to look wild when it's actually farmed, and way too much fat to be wild.
I haven't really noticed any quality issues. I have found it to be better than what's at Sam's Club. It might help that I only use it to make smoked salmon though.
We did have one bag that wasn't the best - which given the price was really disappointing, but generally speaking we've had pretty good luck with the Atlantic salmon.
There was a thread on this on the alien site a couple of years back. These are farmed salmon of lower quality (and is dirt cheap). Costco has a higher quality salmon that they sell, but it's more expensive.