I had both the second version of the Sunset/3rd Rail model (#9030 I think), and the MTH model. Naturally the Sunset/3rd Rail model was more highly detailed and ran very well, but the unique exhaust sound was incorrect (correct sound chip was not available from Lionel) and it didn't have the correct UP freight whistle, typical of all the UP 9000 class locomotives.
The MTH model had superior exhaust sounds and the correct UP "Star Brass" freight whistle. The details were quite acceptable, especially after proper weathering. Both the MTH and Sunset/3rd Rail models had the proper cranked axle with the operating center cylinder main rod and working Gresley valve gear.