I think that a 300 bull is more than realistic on any of those units. Especially on the muzzy hunt. It is obviously tougher if you go archery no matter what you choose. In the past, the fishlake has held some great bulls, but I hunted it last year and we really struggled. But I honestly believe that there are still some really good bulls down there, just a tough year.
I agree with above, it depends on which unit you are the most familiar with and which one you could put the most scouting time into.