The M705 is a clear winner in the comfort category, with The Wirecutter finding it the "clear favorite" among testers. Four out of six liked the M705's size, grip and button placement the best, and it came in second with the other two. However, while Wirecutter says "all of our testers loved it regardless of their hand size," Digital Versus found it "very difficult to get hold of" and uncomfortable for extended periods due to how your wrist rests on the desk while only the mouse moves, which feels natural but is "bad for your wrist."
However, Digital Versus noted that the M705's greatest strength is its battery life, which should last for three years. PC Mag also complimented the mouse's "fast, precise movements" as well as the ability to customize button settings and scroll speed. It isn't going to challenge a good gaming mouse, but the Marathon Mouse isn't designed with long FPS sessions in mind. It's meant for a different kind of marathon: how long you can go without worrying about changing the battery or how your hand feels. And in those categories, the M705 runs just fine.