Really love the first generation of this product. After 4 years and having been dropped many times walking to meetings, the buttons started malfunctioning, so I purchased this model. Overall I like the product, but a few things to note... 1) They used to include a soft case with the 1st gen version. I'm not sure why they couldn't include that again for the premium you pay for this mouse 2) I haven;t had long enough to test durability, but the build quality just seems significantly cheaper in this version compared to 1st gen 3) For someone who uses this device with a laptop and is on the go, the on-off switch on this version is "inconvenient" compared to 1st gen 4) I really like that this version is rechargeable, but interestingly enough, without AA batteries, I really do not care for the "weight" of this mouse as I push it around my desk. I'm sure I just need to get used to it, but personally, it just seems to not feel balanced.