In 1998, I bought a Topeak MTX DX bag and 3 racks (2 normal, and 1 seatpost) for my various commuter bikes. After nearly 14 years, this setup is still used every day. Zippers still work, no tears in the fabric, and the bag still slides on/off easily in a second or two. The only "problem" is the molded panels eventually lost their support so the bag became lopsided. I put a sturdy cardboard box inside mine to keep its shape and it works well. It's not glamorous looking, but it's well made.