I think I tried the Marathon mouse but the trouble was that it didn't have a dedicated middle button. The middle button you see on it only changes the mode of the wheel from smooth motion to clicked motion. If you want to do a middle mouse click, you have to press the wheel.
Now that sounds OK on paper, but in practice I found clicking the wheel to be a PITA. I use the middle button extensively to open browser links in a new tab, and when you click the wheel it's hard not to move it a little as well in the process. Result: you go to click on a link, but right as you're clicking it the wheel moves and the page scrolls a little, causing you to miss the link. It drove me crazy!
So while I liked the idea of the long battery life, in the end I went back to the MX Anywhere model because it has a dedicated middle button, and clicking the wheel changes the wheel mode. That's how it should be.
Actually the MX Anywhere is the only mouse I found which fulfills my criteria of having thumb operated back/forward navigation buttons on the side as well as a dedicated middle button. Every other model I've looked at falls short on one of these criteria.