I've heard the Dexters have a nasty temper, so not sure if smaller but meaner would help. The Highland cattle have those huge horns to deal with and when you sell offspring they are a hard sell to locals who are used to Angus and want nothing else. My sister has raised Highlands for some years now but she's slowly getting out of them.
If I had to choose an all around great breed for a homestead I'd choose the Speckled Park breed, though they might be hard to find. They are a dual purpose beef breed, as they have HUGE udders and produce much milk, do well in cold climates, and even their hides can be sold easily after butchering, so I'm much interested in them. By all reports they are gentle and good mothers, easy to work with. They've got milking genetics in their makeup and to me they appear to be the best of both worlds....and are extremely beautiful, to boot. http://www.specklepark.ca/node/11
I've actually seen these cows and how they perform on grass and it's nothing short of amazing...they stay fat as ticks on grass and are naturally hardy stock, doing well in hot and cold climates, with huge calves that just get fatter on all that rich milk.