^^^ Important advice!... My advice on diving Eden/Grotto is to pick a non cruise ship day...
Also, unless the silversides are in, it's not that exciting (for me). Swim-throughs are fun but boring after a few. Then it all starts to look the same. When the silversides are in, it is fantastic as the life is just explosive with tarpon swimming in and out the tunnels/baitballs as they feed themselves.
Google silversides at Cayman on youtube and you'll see why it can be one of the most fun dives you'll make.
Also, it is not a bad shore dive to do. It's a little bit of a swim but I don't think it's bad. ymmv.