ESF_Island is my least favorite -- Don't get me wrong Stryker, I respect your skills as a mapper but ESF_Island lags & isn't scaled to the models.
The reason I get lag is due to my slow ass CPU speed (350mhz! w00t -- Everything else is good 256mb ram, 46gb hd, cable internet, geforce 2 mx 440).
I have been thinking (dangerous!) and since alot...or all of the default and custom maps by DJ Ready really lag on my comp (and other people who have systems that are 450-600mhz but of course its not all mhz dependent). Did you do with the maps the same thing you did with the models, make then resize? If not the maps should be gone over and tweaked with null brushes and some polygon reduction so the maps won't lag on any comp since most people who play hardcore Half-Life have low-end systems (since it's FUN and they can't play most new games).
I bet you did resize, becuase I've noticed sometimes when I fall onto a slope of a cliff or something i'll get stuck on it and have to fly off.
Anyways, I like ESF_AFM for gameplay