I use Ross switches and mostly Ross/Gargraves track. I went with Ross because many seem to think their switches are more reliable. Well, I can't speak for AtlasO switches but the Ross switches have been very good performers once I got the spring tension right (I use DZ-2500 switch machines).
For my double track mainline I use AtlasO sectional curves to get a consistent and nice looking 4 1/2 inch center rail to center rail clearance (Ross is 4" although they now have some new stuff out). I use AtlasO straights between the AtlasO curves as needed for easy connections, although AtlasO to Ross is pretty easy and once painted and ballasted looks good. I do use Ross/Gargraves and AtlasO flextrack where I can to limit the number of rail joints since I use DCS.
I am also going to incorporate a couple of AtlasO double slip switches because they are #5s and not #4s like Ross'. AtlasO's double slip switches mate up pretty well with Ross' regular switch, although I am thinking of going to AtlasO #5s so I don't have the little kink.
I lay my track on rubber roadbed on top of homasote board on top of 1/2 inch plywood. I make sure the track nails don't touch the plywood, and remove them where I can. Maybe the AtlasO is slightly quieter but since I always run sound I don't notice it.
Both Ross and AtlasO track look good once painted and ballasted, Gargraves less so since it is not spiked down.