Case is good if you want a little cheaper knife that is easy to find, and easy to beat on, and if you want something that is stainless in most of the same patterns as something that is carbon.
GEC has higher overall quality, but can be very hard to find the exact knife you're looking for some of the time, only come in carbon steel (generally), and is more expensive.
Northwoods are more collectible because they're always done in limited runs, but they are made by one of several companies, so they can sometimes have QC issues (though Derrick from KSF will always take care of you if needed). They are a little more expensive on average than GEC, but they have a wider variety of patterns that can actually be found relatively easily most of the time, and KSF is a great place to find anything you need.
Overall, if you want something inexpensive that you can use without worrying, and that will still hold up to anything you can ever want a slipjoint to hold up to, get a Case Sodbuster, or a GEC #71 Bullnose. If you want a Northwoods, get the Madison Barlow, though if you want one of the single-blade versions, hurry, because they just restocked and they'll be out of them again soon, I'm sure. I'm trying to save up to buy one myself before they're out

If you want something a little more specific, then you might have to wander around and see what you like.