Similar to SportsBuy near the end, I think a lot of sellers on Beckett have perhaps forgotten that they are, in fact, "sellers" on Beckett.
I, too, have come around on Burbank. As they have massively increased their volume of listings on eBay, a lot of their prices have come closer to reality. Best to buy from them when they are having a discount or free shipping deal on 10 or more cards.
I try to restrict my buying to COMC where I can sell cards, and then just use my store credit to buy cards I want. Thanks to sales and submission specials, I technically haven't spent any of my own money on there in years.