Try seedland.com, I think they have some comparison info. Like GFR,
I'm not a big fan of Zoysia either. It's a very aggressive, invasive
grass, which can be good except when it wants to spread into areas like
driveways,etc. And being green from April thru Nov in Atlanta pretty
much sums it up.
I'm in coastal NJ and my tall fescue/blue grass is dark green from
April thru Jan. It usually only goes somewhat off color in late Jan
-Feb, and even then it still looks pretty good with some decent color
left. By comparison, a neighbor has Zoysia, and in mid Oct, when it
goes brown, it has a real dried out light brown appearance till mid
May. If it looks like that in Atl when it goes off color, even if its
only for a few months, I'd look for an alternative.