I have been suffering on and off from "mouse shoulder" for the past several years. Recently, it flared up again, and more seriously than in the past. I was looking for a new solution to positioning my mouse and keyboard more ergonomically so that I was not always leaning forward to and reaching out to the keyboard and the mouse. In the past I had tried lap-desks, desk-mounted pull-out keyboard/mouse trays (both the simple drawer type, and the more complicated articulating type), track balls, and forswearing technology altogether and taking up the stone, hammer and chisel again. :-)
It has only been a few days since I have installed my Mobo, and I can already tell that there is a marked difference between this solution and all the others I've tried before. Specifically with the mouse, my arm (and thus my shoulder) are well supported and in a neutral position. No more reaching out to the mouse and hanging my elbow out in space, making my shoulder, neck and back work overtime. The pain I was feeling while using the mouse is, well, gone. Instantly. Simple as that. No kidding. (I'm still recovering, and I still feel the pain when I do other activities that mimic the position my arm was in while using the mouse, but as far as solving the root problem, I think I'm there with the Mobo!)
The added benefit that I have noticed is that I am no longer reaching out to the keyboard as well, causing my shoulders to round over and my back to come off the chair's back rest. I am able to hold my back in, again, a neutral position, well supported by the chair like it is supposed to be.
A reviewer mentioned that he felt the product was "flimsy" and poorly constructed from inferior materials. I was a bit nervous buying the product based on this, but went ahead with the plan that if I unpacked it and found that to be the case, that I'd just return it right away. I absolutely do not find this the case at all. Yes, it is plastic. (What isn't these days?!) The material seems to be high-impact rigid plastic, however, which certainly does not feel flimsy at all. They keyboard tray does rest "out in space" between the two mouse trays on either side, and it might be a little thinner than I'd like (giving a bit more "bounce" while I type than I am used to), but flimsy? No.
Another reviewer mentioned that he found the keyboard tray to be a bit too slick, causing the keyboard to have a tendency to slip about a bit. I have found this to be accurate, and am going to go out to Michael's today to spend the $0.84 on the solution he implemented.
Finally, another reviewer mentioned that positioning the keyboard properly took space away from the mouse area. I do not find that to be the case in my instance, but I have a wide "executive" style chair, giving plenty of room for both proper keyboard positioning without encroaching on the mouse pad. I could see, however, where this might be a problem on narrower chairs.
I do find, however, that the keyboard is up higher than I am used to having it. Again, I think this is a function of the design of my chair, and not at all anything to do with the Mobo itself. It is not uncomfortably high, and in fact, I am noticing that my wrists are in a more natural position, so maybe this is a good thing.
In the end, 110% worth the money I spent on it. Had I spent the same amount and threw everything else away except for the chair-mounted mouse pad, I'd still call it well worth the cost, given how dramatically and instantly it solved my shoulder problem.