I like the minis for binding; I find that they're just the right size. The markings on the flat side are great for keeping the binding straight.
I have some of the bigger ones, as well. I use them for organization more than when sewing. For example, if I'm making 200 HST's, I will clip them together in sets of 10 or 20 (or some convenient number) so that I can keep track of how many I have.
The large ones would probably also work for binding... I got them after the minis, so never tried.