I agree with what several others have said.
Is the Mauser is going to remain "stock"?
Do you reload?
If both guns remain stock (apples to apples) then it's a wash, whichever one you can hit with more consistently.
If you intend to scope it (recommended) then the Mauser will cost more, bending the bolt (unless it's one of the bent bolt models) but the receiver will have to be drilled/tapped for scope bases. Probably less than 50 bucks to do that. The Marlin comes already drilled/tapped.
There is no such thing as a "brush busting" bullet. Mike Venturino did some fairly exhaustive testing probably 30 years ago, and found that the high velocity "pointy" bullets actually fared better than the blunt "woods gun" bullets.... but both types were wildly unpredictable when shooting through "brush".
Caliber wise, the 6.5 is considerably better than the 30-30. It shoots flatter, and its "standard" bullets (140gr class) have a much better sectional density than the .30cal flat or round nosed slugs. Better penetration equals better killing power.
However, the 30-30 is next to perfect for deer out to around 150yds or so, if you can put the bullet where it's supposed to go.
If I didn't reload, and I was only going to hunt deer/hogs at normal woods ranges, I'd more than likely get the Marlin.
If I thought I'd be hunting something larger, or further away, I'd pick the Swede, and buy good ammo for it online, if not available locally. If you reload, your ammo choices are almost limitless.
My "go to" deer rifle is a Carl Gustav Swede that I sporterized myself. It drops deer like a hammer. One shot, every time. (so far)