With minimal matching, however, the engine backtracks after every character. The first thing it tries to match is ", and it fails every time, then backs up and tries matching .+?, until it finds the ". It's doing more work that way, so it's slower.

No, perhaps you are confusing .+ with .+?. With .+?, it's inching forward a character at a time each time it can't find a " immediately there.

-- Randal L. Schwartz, Perl hacker