I think it depends on many things. IMHO, riding one of the regular enclosed coaches is a more authentic ride, i. e. more like what the trip would have been like in the 40s before the Silverton line was discovered by the tourists, unless, of course, you get a chance to ride in the caboose.
Riding an open gon would be my choice in good weather. Better visibility, and the coal smoke and cinders have a better chance of helping to make your day memorable.
The Silver Vista, hmmmmm.....Rather nice historic recreation. Ride it if you like, it certainly would be a good experience. Worth the extra fare? I'd rather put the money into a caboose or cab ride.
Just my opinion, and that's worth exactly what you paid for it. Whatever you decide, enjoy your trip, it will be well worth it for you.
Ed