NEW Logitech M720 Triathlon Wireless Mouse

Ever since I bought my first Logitech mouse many years ago, I've been a strong believer in the quality and care found in Logitech products. I've bought 40-50 Logitech items, from mice and keyboards to speakers and specialty products over time, and always but always been totally happy with each; all working perfectly out of the box, and on the rare occasion I've needed tech support they've been there with fast and superior assistance. That includes the fantastic support I got after purchasing the M720 Triathlon Mouse which delivered with a faulty scroll wheel. No matter what I tried, I couldn't get scroll function; everything else worked. So, out of the box maybe 20 minutes I contacted Logitech support through online chat, and less than 20 minutes later a replacement mouse was arranged for delivery to me under warranty. The replacement arrived just 2 days later, and worked 100%. Now, just 5 days later, 3 of which it wasn't in use, the replacement mouse's scroll wheel function has "dropped out" several times; just suddenly not working. This prompted me to do some looking around, and while I won't say it appears to be a prevalent problem, it's one I did find many others had also experienced. So far, I've been able to regain scroll function each time by flipping the mouse upside down in my palm and tapping the underside straight below the wheel area. Scroll function operation is made in much the standard method, with an opto-sensor circuit, but it's not a one piece counter; it's an IR emitter and separate receiver mounted on the circuit board. Given their close proximity I can't hardly imagine there's an issue of mis-alignment going on, but it's either that or a poor contact on the PCB. Either way, having got one DOA and it's replacement quickly showing sign that it may also suffer the same issue it's not encouraging. One additional issue, unrelated, which I've quickly found at least for myself to be a feature I've quickly found I actually don't like (and have disabled for the moment) is the "thumb button"; an added button hidden right at deck level in the flare of the skirt beneath your thumb. I love being given an extra, customize-able control, however I've quickly found my normal hand position makes it too easy to activate this one accidentally about every time I move side to side. You've got to keep your thumb held higher up on the side to prevent setting it off. If you were used to a button in that area it might be okay, but if not this one activates so easily it will have you frustrated quickly. Purchased as a replacement for my M90 which I've used so much the left click is starting to get weak, I think I chose the wrong model as a replacement. I'll be shopping for another, and it'll still be a Logitech, but it won't be the M720 Triathlon. I'll probably spring for another MX Anywhere Silent Click Darkfield Mouse.