I'll make it as simple as possible....There is....NO difference between the current up to date Fan TL and the official JAST version. play either one and you'll get the same game. I recommend the JAST version since its easier and quicker to patch. Though don't actually BUY the JAST version since you'd be supporting JAST....who takes 8 YEARS and counting to TL one game.
No, the fan TL was still in Japanese for H-events and some actual events that were not in the PS3 version of the game. It's a direct port from that version basically. This version on the other hand probably just has a few word differences from it and TLs the missing events...and apparently removes the mosaics. (thank god)
The fan TL is incomplete and has mosaics, as far as I am aware this version is fully translated and no more mosaics... Someone correct me if I'm wrong on the mosaics part.
Pasa forgot to add that Grisaia no Rakuen Translation work is done, Engine Work and QA in progress VALLOTH VICTORY (Inside joke, get on the shoutbox more scrubs)