This is an unbelievable bag for under $45. I got it a couple of weeks ago, strapped it onto the sissy bar (no cargo rack needed) and have been using since. The bottom (larger) bag is plenty big for rain gear, gloves, backpack straps (yes that's right it even converts to a backpack if you want to take it with you when you stop), jacket liner, lunch bag for work and ther's still room to spare. The material is great quality, holds up to a light rain without getting too wet, comes with a rain cover that fits over both bags for those heavier downpours.
Only a couple of slight negatives (why I gave it a 4 instead of 5). The metal clips on the straps used to hold the bag down seem pretty flimsy and probably won't last very long, we'll see. And the bag doesn't hold its shape when empty or partially empty, just doesn't look right when the top sags a little.
I had been pricing bags for weeks and found this one at half the cost of the next least expensive bag. So even if it lasts my half as long as the other would have, I still don't lose, but if it lasts me just as long as the other could have, then I've won.
Viking Bags was very good answering my questions on this bag and shipped it quickly.
Overall VERY impressed. Can't wait for a long trip to really test it out.