My fiancee and I were really impressed by the quality of the engagement rings sold at Birks and were very happy with the services provided.
We had a small budget ($2500-$3500) and although we could get a larger diamond from budget retailers like Peoples, the quality of the setting those diamonds were placed in don't even compare. The craftsmanship of the Birks rings are well worth the higher cost.
Rather than "sizing" the ring you choose, Birks has the diamond re-set in a brand-new setting in your size. The only downside to this is that it takes 5 weeks to get your ring!
Birks also offers the best payment plans of any jeweller we visited. We opted for a 10-month, interest-free payment plan, but they also have a 20-month, interest-free plan available as well as many other financing options. This allowed us to shop at the top of our budget, which we couldn't have done as easily at Peoples.
Finally, the salesperson was very helpful and did not try to up-sell us beyond our budget even once. They did not use high-pressure sales tactics and were happy to let us take our time.