I stand by my previous review (paragraph directly below) but have added to it.

I hauled this thing to Montana on the back of my Harley with a double wide sleeping bag, 10'x12' foot print dome tent and pairs of backpacking type air mattresses and pillows.  This thing held it all and held together.  I am very happy with the bag and may even buy some of the smaller ones for other uses.  The only reason I gave it 4 stars instead of 5 is because it would have been nice to have compression straps going the other direction as well.  I needed it wrapped as tight as possible for the  bike but a bungee cord took care of that.  It also kept the rain off of the contents for the few miles I got rained on.  Overall, I think it is a great bag for the price.

In that review I mention possibly getting some more.  I have. I now own XXL, XL and am buying the large.  These have been great, durable bags that I find easy to attach to the bike.  I would still like some compression straps running both directions but there are enough handles and loops for me to tie things down.  I keep buying more sizes just for the flexibility of deciding how much luggage I need for a given trip and minimizing my luggage.