Size of motors drives a lot of choices... I'm building the M60 in 1/6 vice 3' long because the 1/6 scale makes the hull 14" wide to accomodate 2 of the motors Joe Sommers sells, without any arrangement heroics.
On that note, Joe's Hetzer is built around cordless drill motors, so I'm guessing they work alright.
-- Clark M60A1 "the Beast" under construction KI4GYT --
Why do tankers call infantry "Crunchies"??? Because they ARE!!!