Okay first off I'm not being modest when I am saying this so please don't think that i am.
I have been keeping and maintaing a 20 gallon reef tank for almost two years now. A fleck of the iceberg compared to many that frequent this forum. These are the people I ask for help when I run into problems, even then i try to use multiple sources then make my best judgment as the correct course of action to take.
I don't know everything, I feel I don't know alot about saltwater so for someone to call me knowledegable in terms of saltwater conveys to me how little they know. I WILL tell if I don't know something and I will try and help anyone to the best of my abilities.
now, based on my own experience if your buying corals your buying aptasia. I have gotten aptasia from Midway tropical fish and pet, blue sierra, barrier reef and even one from the all mighty Todd of cherry corals(my presonal favroite coral dude) it is up to you as the hobbyist to keep those in nasty critters at bay.
mytemouse here on reefrontiers is someone that I would refer to as an aptaisa nazi, as he eradicates them with extreme prejudice. I would ask him for tips and pointers in that process. In terms of avoiding aptasia on livestock by avoiding stores.....well that eliminates all of them, all of the time.
Your best bet, regardless of where you buy them, is to inspect the coral the best you can previous to purchase and before it moved (those little buggers close up to literally nothing...its rather amazing really)
There has been talk (alot of talk, just talk, I wish it were more then just talk) about a newer updated saltwater section in the works at Midway, until I see that sucker materializing into reality I will continue to diligently spitshine the turd that I have (or until I start classes again and he has to replace me with a full time emplyee). When/if a new system does get installed there you better blieve me when I say I will fight tooth and nail to get it setup right.
"spend the money up front so you don't lose it in the long run"
-just made that up but I bet you somebody else said it before me-
sorry about the rant, but I havn't slept yet bare with me...
rant over, commence fishing
(btw the puyallup river is REALLY cold when you don't have waders and you go fishing at 5 AM wish me luck)