I just bought some Bushwhacker panniers from the manufacturer. For Summer cycling these bags are great. Their prices are excellent. In 3 years, you can buy a new set and get the latest technology.
They arrived today. Super product.
Looks like 1000 D coated fabric. Zippers are sturdy #7 with pull tabs. I got the Montezuma (mislabled on their web page -- it is the "Yukon" on page 2). It's 3000 cu in. total.
There are two side panniers linked together with a sturdy cloth strip (making them easier to carry as luggage when running for a on-time European train). Each side has a large 800 cu in (approximate size) compartment, a backplate, and covered zippers plus a 200 cu in rear pocket AND a small side pocket on each. Then there is a separate 1000 cu in zip-on top compartement that covers both side bags and the rack. If I add a wide, long shoulder strap, I think I can hang the whole thing from my shoulder as I pilot the bike between trains. That's important for me and I prefer some smaller pockets too. They don't need, or have, top rack hooks because the cloth connector has velcro attachments but there is a bungee corded hook at the bottom for stability. Lifetime warranty.
A really nice product.