The Atlas is a flat, "covered pit" design and is pretty ugly.
The Walthers turntable looks great and is indexed, but expensive.
I have a Peco turntable. It is rather short, but will hold up to a Kato Mikado. The couplers will almost overhang the bridge on the Peco unit, but it fits. Mine is powered and I found it on e-bay for about $89. It is a good looking turntable that does not take up much space. I don't need auto indexing. It will be used as part of my model of the Danbury Railway Museum as part of my Housatonic layout. The Peco turntable sounds like a great option, especially if you want it unpowered. It has good detail, including the cast bridge drive motors and cast in pit track. If you want to turn anything larger than a Kato Mike, then you will need to look at the Walthers turntable.
Eric