Lionel has always been confusing to me. It's the main reason why I shied away from getting involved in any of Lionel's motive power. TMCC, TMCC with Odyssey, Legacy, Cab-1, modules for Legacy...I could never figure it out.
MTH's DCS was easy for me. When I started it was Protosound-2. I quickly found out and stayed away from any engines prior to Protosound-2. DCS works with PS/2 and PS/3. Also, Railking is semi-scale (except for some smaller diesels and switchers) and Premier is scale(with more detail). Both work with DCS. Railking product numbers begin 30-, and Premier 20-. Easy!
This is not a Lionel vs MTH reply. Just my rant. I have Lionel rolling stock.
I want to run trains, not be an electronics wizard.