It really Depends on the size of your scraps. I have a Studio, a big cutter. The dies for it are heavy, but they work well. So if your arms and hands don't like heavy or don't work like they used to, get the Big electric. The dies are lighter and I don't think they cut as many layers, but they work well.
Types of dies: I use strips a lot, followed by triangles and squares. I don't applique, so not applique dies for me.
Dies are expensive, so buy what you need when you need it - and when it is on sale.
I agree that the website is confusing. Sometimes I think confusing web sites are confusing to get you to 'look' longer in hopes you will buy more!