We took the "Orient Express" train about 4 years ago, right after it started up. At that time we paid $30 for the tickets that included lunch. The views were breathtaking for the first half of the trip and, since we only traveled about 30 miles per hour, we enjoyed the open observation car and got some fantastic pictures of the Andes. The huge windows and the comfortable seats were great. We stopped at 14,000 feet and did some "shopping" at the impromtu market along the rail tracks. The last part of the day did seem very long as the views closer to Puno were not remarkable and the 13 hour trip was pretty long.
This year I am planning to go back to Peru and will again make a trek from Cusco to Puno. I'm planning to take one of the busses this time, primarily because the cost of the train is so much higher now, and because I'd like to do the trek in a lot less time.