For the man power cost of an infantry section and the fuel cost of a halftrack you can completely lock down a section of the map 360 degrees for 5-10 minutes. It doesn't even matter if it gets destroyed you can just build another and the advantage it already gave in map control means you don't need to rebuild them anyway. And if you go advanced emplacements infantry section can build them and have them out really early on.
I feel like Ostruppen gives you a stronger early game but Defensive has more for the late game but there's no where to dump munis on Defensive. The sector arty is kind of meh but the railway arty can be devastating.
M10 is a joke, since it is only useful as a throw away tank to trade for a super heavy in a risky dive.
That's not true. The M10 is very good at it's role, which is to counter medium tanks. You rush one or two out, counter axis' mediums and unleash the damage with the howitzer Sherman. Also the M10 is a beast at crush damage and is an unorthodox way to deal with blobs. Combined with the dozer sherman you have a lot of wipe potential.