I never really got the point of single investigator games, it always limiting because you cant assign roles to different people, you enter another world and by the time you return to Arkham more gates have opened or the place is overrun by monsters.

I sort of like the idea of a single investigator playing two turns before every Mythos phase and I think they should have put that it in the original rules.

Im currently playing a PBF game which is fun but because of the downtime you do end up thinking more about the aspect of gambling and probabilities in the game. Its a lot easier to see the best options based on your clues and resources.