I have a Dahle 533 and have been very happy with it. It's a 12" guillotine style cutter which says it will cut up to 15 sheets of copy paper at once so it's more than capable of cutting cardstock. It's a self-sharpening blade and has a good sturdy metal base. You probably wouldn't want to tote the thing around with you but it's great for a cutter you have on your work table.
I shopped around and got a decent price on eBay, there are a couple on US eBay at the moment at around a hundred bucks which probably gives you a ballpark price if you're comparing stuff.
There's a little YouTube demo here