I've done some pretty extensive research on window protection before deciding on the aluminum panels. I highly recommend the panels due to price, ease of installation (once hardware is installed) and very easy to store.

The one draw back of the fabric shield is that If an object strikes it with enough force, the fabric shield will deflect enough so the object will still break your windows. It also costs much more than the aluminum or steel panels.

Lowes carries the panels and various mounting hardware, but I highly recommend getting thru your local contractor supplier.

I got my panels from ASI in Orlando.

Of course the very best window protection is whatever you get and install.