I would hope that this is a designed as a smart load-balancing multi-link tunnel to Shareband's servers and not really just a simple load-balancing router. A simple load balancing router would only max you out at the throughput of the fastest link that you have. A multi-link tunnel should max you out at nearly the sum total of bandwidth for all tunneled links.
Well, that's assuming one download. If you're downloading .. say a Fedora Core ISO, then you're limited to the fastest single link If you're downloading many files (or hosting services), then, a load balanced server will give you high throughput. The key with a load balanced setup is that you're balancing connections. Bonded will give you the sum of the two, in theory + a little overhead. -- Canada = Hollywood North