Jim,
The first time I rode the "Silverton" was in 1953 in the Silver Vista so what Im going to say may be biased. My feeling is once you ride the Silver Vista you'll never want to ride anywhere else. The same was true riding the vista domes on the old California Zephyr. The dome was the only place to ride. While the old coaches give you a sense of the history, the scenery is mostly above your head and that cant be seen from the coaches or the roofed open cars.
The Silver Vista is fabulous and I believe has the same service level as the parlor car.
Just my opinion
John Bush