I decided to purchase the EM03 Trackball Mouse, despite the negative reviews, because I just love my ProtoArc brand EK01 and EK01 Plus ergonomic Keyboards and wanted to also try their ergonomic mouse (trackball). So I have read all the mixed reviews, and I can honestly say that I don’t see where the negative comments are coming from.In regard to those that say the trackball is not smooth or “sticks”, I have no such issues and I do not even see how that could become an issue. As an engineer myself, I think the design is very creative and would be less prone to developing issues than one that spins on rollers (like the original old school mouse!).I also have had no issues with connectivity. It quickly and easily connects both with the USB dongle or Bluetooth.In response to those that say its uncomfortable (to big or oddly shaped), that is completely subjective and you shouldn’t bother leaving a review to tell others you just couldn’t get used to it… That’s on you, and shouldn’t sway someone else or knock the product (star rating) for that. I would admit that it takes some getting used to, just as anything new or unfamiliar. You get used to how a new vehicle handles, and you adjust accordingly. Same thing here. And I find it to be very comfortable and easy to navigate my 3-screen setup. It takes some getting used to with the new button placement however, you can and will adapt so long as you try.It is a very different feeling than we have been used to with the traditional mouse and button arrangement, but it feels fluid and natural. The biggest thing I struggle with is using my thumb to operate the left-click; as well the button are sensitive therefore Im making some erroneous clicks. Im learning to just keep my thumb on the scroll wheel and then move it to depress the button when needed. But Im still on day one using it, and Im adapting to it quickly.For those that reported negatively that it does not give an audible or tactile “click,” well apparently, they didn’t read the ad! The ad makes it a big point that it’s nearly a silent click. And therefore, one should expect that given the nature of making the click silent, the tactile “click” feeling will too be significantly less. There is still a tactile click, but its very sensitive. So those that say they can’t feel it, they just simply don’t have enough sensitivity in their hand to notice. I don’t see how this would be a problem for anyone, but to each their own. And again, comments like that while its fine to let others know your feelings and opinions, you shouldn’t make it as if there is something wrong with the product and to rate it poorly because YOU didn’t like the fact that you don’t get the “click!” The product ad does NOT try to hide this fact, again, they make it a blatant selling point! So you should have bothered to read it (or look at pictures that displayed this) and then you wouldn’t have wasted your time with a product you knew you wouldn’t like… because it doesn’t click.As to the battery life issue that some have reported, I can not attest to that, Ive had it for a day now. However, I can say that being it’s a rechargeable lithium battery (from China) they are made in bulk and every so often poorly made ones get through QC. While the manufacturer of this mouse will check to see that it powers on and functions properly, they would not be able to test the battery’s life span. The truth is, besides the occasional poorly made battery, these battery’s chemistry is highly volatile, and they can go bad suddenly and without warning. Not to say they are not safe, but we all remember the cell phones blowing up, right?! And on the other side of this, some batteries could have sat around for a long time (either waiting to be purchased by some manufacturer to be used in some product or sitting already installed and in a warehouse waiting for some consumer to buy the item (like this mouse). Either way it happens, the thing is that lithium batteries don’t like to go long periods of time without a charge. More especially, if they didn’t have them charged to a minimum at a specific “storage voltage” and the voltage was below that value (likely after having tested the product) then the batteries are likely to degrade much faster the longer they sit around not getting a charge. And then some poor consumer buys the product with that battery, and automatically blames the product and the brand for having a bad product and for people to stay away from them. This can easily happen with any lithium powered product and not limited to poorly made brands, can happen with big name brands too. That’s why they have return/exchange and warranty procedures in place!This got way longer than intended, I just feel like Im tired of seeing people say things about a product that are completely subjective, even it’s a good product.I am in no way affiliated with this product or brand, I am a happy customer that bought this brand’s products and feel that people should have a right to know that its still a great product regardless of a few “bad apples.” And don’t rate a product badly just because you aren’t in love with it or have some personal gripe (this goes for any product). Write your review, get your feelings and opinions out there, but if the product PERFORMS as advertised its only fair to rate it against what is advertised, not the fact you just couldn’t get on board with it!Give it a shot, the worst that happens is your just not satisfied with it and return it. If you keep it and something happens months later, go through the warranty and get it replaced. They offer a 2 YEAR WARRANTY on their electronics; this is straight from their website and it covers Amazon purchases!