We use Atlas track for new alignments at the club and it joins perfectly with Ross turnouts. DO NOT use the Atlas adapter pins. Cut the stringers from the end ties on the Ross turnout, slide the end ties back a bit and use regular Atlas track joiners.
Here are some shots of Jeff Waldman (sphillyj) and me cutting a crossover (2 Ross 11-degree/#5 right-hand) into the mains (Atlas-O).
Here's the left-hand crossover at the other end.