Need tractor advice

Some good friends are going to be shopping for a tractor or the like in a couple months. They've got about 3 acres to cut and also plant a kitchen garden and patches for wildflowers. They'd like to be able to mow down light brush, too. They have a push mower for the lawn around the house.

I agreed to lend an ear to this enterprise, but it's the blind leading the blind, heh. Plus they're "income-challenged" so they're thinking used equipment.

Here are the possibilities they've been bouncing off me, as if I know anything. Except I've been trying to think of all the pros and cons of each. The links show examples, but not necessarily the make/model. They'll decide that when they look at what's available around the end of February.

Garden tractor
Compact tractor
BCS equipment (two-wheel tractor)

Or use animals:

Fence
Pig - the "tiller"
Goats - a/k/a bush hogs
Geese - grass trimmers

I'm not certain if they'd rather maintain an engine or care for critters, and it sounds like they're waffling with that, too.

Anyhoooooo - I'm actively soliciting advice on their behalf from folks who've got to be more equipment-savvy than I am. In other words, everybody. Brands to avoid, livestock versus machines, reliability, cost of upkeep... Whatever. Opinions are like you-know-what's, everybody's got one. Post yours in the comments and I'll pass 'em on :-).