I'll chime in as I've actually built the Revell offering and I can comment on it.
I was building a similar Dio as what you've planned, and I actually have a photo from the planning phase:
The Panther is of course, Revell, with Tamiya putty zimm I applied with a fine saw and wire and railroad mesh detailing. My aim was to end up with a similar configuration as these photos:
My aim was to show a German Panther being caught in route by American combat troops after the Normandy landings, as my reading indicated that the Germans preferred to move heavy armor by rail rather than risk engines and transmissions in long route marches, and this example was stopped before it could disembark and join the fray.
The Plattformwagen and track is a heavily modified Verlinden example and the Figure is a Preiser World War 2 American.
I bought about 4 feet of 1/72 Italeri track to build this dio, but never got to the finish.
The Revell kit goes together well, the tracks are link and length and it looks the part, but I never made any detailed measurements.
I bought 3 off eBay for 16 dollars, so deals can be had. Good luck!