I have bought parts from bestbuy pool supply as well. No problems.
When I had my pool opened for the first time after construction the guy refered to the multi-port valve as the $400 valve, as that is how much it would cost to have it replaced(including labor I assume). Funny part is that, by him referring to it in that way always led me to remember to shut off the pump before moving. Funny how, if you attach a dollar amount to something what you won't forget.