It is my understanding that Zoysia is a type of bermuda which is why we voted against it for our back yard which is mostly full sun. I hate hate hate pulling bermuda out of flower beds but pulling St. Augustine is much much easier.

Right now our yard is a mix of both until the St. Augustine is done over coming the bermuda.

Brown is brown, its the same to me. The grass is dormant, that is what it does, it dies back and isn't green anymore.

Our St. Augustine is greener now than the bermuda -- It stays green longer in the fall than bermuda.

Bermuda doesn't really green up and grow until it gets much hotter. And it does tend to go a little dormant again long about Aug to mid Sept unless you keep it watered really well.
(perhaps its the same for the others? I never really noticed because we keep our lawn watered)

I don't think the Zoysia up the street is nearly as lush and green as our bermuda in the front yard --right now.

However.. in my opinion a dormant lawn of Zoysia or bermuda does look nicer than a dormant lawn of St Augustine. But that wasn't one of my considerations when choosing which grass to go with.

never seen a brown lawn of St. Augustine. But then I am in Galveston and have no grass-I dug that stuff up and put in plants!
Good luck.
Tally Ho!

I never put in a lawn. Just native bunch grasses here.