I got sidetracked on a major project for a customer, but I've finally gotten back to this--you asked me to write you about some of the features on the Grand Millennium that were specially suited for motorcycle use.
In our conversation, I mentioned a similar product made by the RedOxx company in Montana. I've considered buying it for this purpose, but your product is better suited, I think. Here is a link to the product: https://www.redoxx.com/Airline-Carry-on-Luggage/Safari-Beanos-Bag-PR5/91031/100/Product This is a $220 product, so it's hardly cheaper than your offering. RedOxx makes some superior carry-on luggage that I've purchased and liked.
The reason I don't think that the RedOxx product is suitable for motorcycle use when compared with yours is partly basic and partly practical. It's not as water resistant as yours, and some of the things I carry in your bag would wear out the RedOxx product more quickly.
I'll try and explain why I think the extra-cost use of leather made your product especially suited for the intended use. When I originally bought your product years ago, I thought it was a bit balky to use leather in some places, such as in particular the large side pocket. However, after years of carrying M/C gear such as disk locks, tire patch kits, CO2 inflators, Leatherman pliers, and a variety of similar things in that pocket, it's still going strong while there would be holes in anything else.
The central and end compartments are usually where I store clothes and stuff. The top item in the central compartment almost always is a small, notebook computer such as a Toshiba Satellite (11") or something similar. I've carried computers that way for years, and the bungee net I often put over the top of the bag (as in the picture I sent you) doesn't do any damage to the computer in part due to the heavy leather flap on the top of the bag. This is true even when the compartment is (as usual) stuffed pretty tightly.
I also manage to wrap a spare (clear) helmet shield wrapped in plastic wrap around the end of the clothes bundle in that pocket--it's the right size for that (Shoei X11).
The end pockets often are stuffed full of pointy items that might puncture Cordura over time, but which do not puncture the leather. A total of 17 years of use and over 150,000 miles haven't done in these features, which I think it very remarkable.
For quite a few years, I used the bungee cords included in the bottom of the bag for the basic attachment. I'd usually put a bungee net over the top of the bag, which allowed me to put items on top of the bag that I might need to access during travel. Almost ten years ago, I found a better way to attach the bag to the bike, so I removed the bungee cords and started to use that bottom pocket as a place for a zip lock bag of documents or other extra thin stuff. From the picture I sent, you can see that I use a hookless bungee net to secure the bag to a set of permanently mounted swingarm spools that I re-purposed for this. It's easier to get the bag on and off the bike that way. So it's good that the included bungee cords are detachable--another bonus pocket.
As we discussed, I'll send you the worn-out rainfly for my bag that you offered to replace. Thanks.