I use Airtites but also use Intercept Shield (IS) holders stored in IS boxes for added protection. Try Wizard Coin Supply or Brooklyn Coin Supply Galley for decent prices. TC
The only problem I have with airtites is displaying them, its so hard to store them in an album, and for a 54 slot album its almost $30 for an entire lincoln set thats a lot of albums.
If you're talking airtights, the foam ring is used to allow use of a particular size airtight for slightly different diameter coins. Direct fits are for a specific coin. There's no difference as to which one is better.
I have been using the CoinWorld Premiere Holders for my best coins (nothing too great). They are the same size as the PCGS cases, so they fit in the PCGS plastic boxes. I like that you can put the description of the coin on a little tab in the case, just like PCGS. I had been using the airtights, but the circles didn't work for me, they always seemed to be just floating around somewhere. They are slightly more expensive though. I also use Wizard Coin Supply, and have had great experiences with them every time.