The Lionel S3 has the steam chest smoke and stack smoke that share the same reservoir. There are issues with filling it properly. Make sure you fill them properly before you cook your smoke unit. Also the older motor driver board had some stability issues.
The 765 is a better bang for the buck. Great Sound, and fantastic detail. The bushings fell out of the pony truck, but a tad bit of super glue and you are back in business.
Another Legacy hit in the 4-8-4 wheel arrangement is the GS6 or GS4 Southern Pacific Locomotives. Best whistle out there.