I've ordered online and from LFS.
LFS: I bought from Atlanta Aquarium (Rit) & Nemo's multiple times with no issues. However, I would call Rit to make sure he has any tho, he's been doing less and less marine fish & inverts. Also, the past couple times I been to Nemo's, he's had bumblebee snails, but I would call to find out first if its a long drive for you.
Online: Only experience I have is from reefcleaners.org. I've used them twice. Both times I had no issues, however their CUC are TINY!!! I can't emphasize that enough. They are a fraction of the size of what I would get from AA or Nemo. I only use them when I am trying to get hard to find CUC.