I went to the Alligator Farm around this time last year and the place was CRAZY busy with activity. Screaming baby Egrets, Spoonies and everything between. I have never been to Gatorland so I can't give you a comparison of the two, but I really enjoyed by time there. Great for flight shots. Babies are so close you could reach out and touch them. I bought a photographers pass when I went which allowed early and late access to the rookery before the general public.
I was there 2 weekends ago and had a great day shooting. The birds were superabundant and there was good variety of species. I highly recommend it. If you like shrimp and seafood, Osteen's Restaurant is a mile or two down the road toward St. Augustine and is a great place for lunch.