I attended our airport pilot's association pancake breakfast this morning, which is usually fun and always interesting because our ATC peeps, the airport manager, and some of our local vendors often speak and share the latest relevant info.
Our self-serve fuel vendor usually shows up and today he provided some insight on his perspective on the current state of the unleaded fuel situation. One very interesting tidbit is that he's sensitive to the liability concerns, e.g., if somebody has an issue because the new blend weakened a gasket and a leak caused an accident, he could be affected. He said his insurance covers the first $1M of a claim, which doesn't go very far in an aviation accident, and the distributor adds $50M of coverage on top of that. GAMI does not have a distribution system which adds any coverage, so that is a serious issue.
He also indicated that Swift is actually pretty far along and may have distribution rolling soon. The expectation is that once their 100 octane is being produced that they'll drop their 94UL and sites currently selling 94UL will instead sell the 100 octane. He also said that the Switft blend is very different from GAMI's, in that while GAMI uses aromatic solvents (xylene) which may affect finishes (paint) and gasket/seal integrity, Swift uses oxegenates. I took this to mean that the potential issues with finishes and seals, etc., would be expected to be less.
Anyway, just passing it along. Don't shoot the messenger, and I don't really know any more than I'm passing on.