L.A.
I guess which one you get, depends one what you want to use it for. I have the smaller one and am very happy with it. I just use it for basic scrapbooking, lettering, small pictures etc. If you are looking for something beyond that, making banners, decorations etc, go for the bigger one.
They do all use the same cartridges. Check out the website customcrops.com They have great sales on the cartridges, and machines.