The Queen Street location has a huge selection of yarn. As other have said the main floor has standard pricing while the basement is full of options that are at a significant discount from the regular price, you just have to either totally luck out or not care what colours you want to use if you are going in for the bargain basement buys. Sadly though, although I find colours I like down there they never seem to be the ones I am specifically looking for, for the project I am shopping for and I TRY not to buy random wool (I have to admit though that I sometimes fail at that mission).
This is not the place to come looking for inexpensive or non-natural fiber yarns. They might have a few running around the store but their focus is on natural fibers and specialty yarns. They also have a nice mix of needles if you are looking for that missing size and the price point there seems to be fairly standard.
Staff is hit and miss. 2 out of 3 times I will get a totally fantastic person who is really interested and lovely to talk to with tonnes of suggestions... that 3rd time I get the person who barely grunts at you.
All in all I love coming into this shop to look around, be able to check out yarns that I might not have had access to before and plot out my next WIP.