I bought this WEP410 to replace my Samsung WEP200 headset. The 200 was itself a step up from the Plantronics Voyager 510 which was highly rated, though I found the 200's sound quality, connectivity via bluetooth 2.0 instead of of the Voyager's 1.2, inconspicuous size, and price to all be superior to the Voyager. But the 200's sound was still a little muffled, and the fit was earbud-style which wasn't always comfortable for my small ear canals. After reading tons of reviews, I settled on the 410 here for its size, quality, brand, and price.
The WEP410 has a more comfortable fit, provided you don't mind an in-the-ear-canal design. Just slide it into your ear and it's all good, it's simple to work with and an easy, almost unnoticeable fit. The biggest drawbacks for me in terms of fit are that it causes me to hear my own voice in my head as it does plug the ear (it doesn't cut off all outside sound tho'), and my ear canal gets a little sweaty with this in direct contact. I also like the fit on the 410 because unlike the 200, I can quickly and easily switch from ear to ear - most folks won't tell you this, but ear canals aren't usually the same size, where my headsets fit fine in my right ear, my left is slightly smaller to the point of causing problems fitting the 200, while the 410 here slides right in (though a little more noticeable than on my right) and this is true of most folks I know.
The 410 is slightly longer than the 200 but narrower and 1.5 grams lighter (both the 200 and this 410 are extremely lightweight, yet feel robust rather than cheap). The silver at the end says "hey, look at me, I'm wearing a bluetooth headset!" but it's still a fairly discreet design compared to the vast majority out there. The LED this time is less conspicuous, a ring around the main button (the light can easily be shut off, though you have to do it each time you turn the unit back on); the button itself is a lighter press but still tactile enough. The 410 suffers a larger carrying/charging case than the 200 due to its shape and earbud, but if you happen to carry your headset in a purse, this will help keep it from getting lost or damaged; I just throw mine into my pocket (that's a risk of it turning on and redialing, but hasn't happened to me yet).
Incoming sound quality is very good, bordering on excellent, the only "what?" moments I have are when I'm talking to friends on their inferior headsets. Outgoing sound quality isn't quite as good since noise-reduction is a little overly ambitious in the car, and there's a slight "hollow" sound folks seem to notice, and it doesn't cancel the background all that well, but it's still vastly cleaner sound than anything else I've used so far and avoids nearly all the "what?" moments on the other end. Connectivity is good but a tiny bit more chance of static than the 200 depending on obstacles, still it generally works out fine, especially while driving.
Functionality is where this unit takes a hit. While the 200, and nearly every other headset out there, use a single button press for accessing voice dialing, the 410 uses that press for redial; the 200 used a 2-second long press for redial, where the 410 uses that for voice dial. However, it's not that difficult to get used to, and it makes an audible sound when it's redialing so a second tap can hang that up quickly. Like the 200, the 410 doesn't play your ringtones, instead it has its own simple tones for incoming call and text message.
The volume controls are pretty small yet still tactile, but they're so high up the body (one on either side, unlike the 200) that I either have to move the unit or press my ear cartilage to depress the button facing down - this is fairly minor though. Pairing the unit is quick and simple, but I haven't run into a headset yet that wasn't, including a couple other models I sent back. Turning it on and off is a 4-second hold on the main button, 1 second shorter than the 200, and for shutdown it makes a unique double-hang-up sound AND flashes blue then red. In terms of battery life, I haven't run into any problems, and it charges quick enough for me.
All in all, I am very happy with this bluetooth headset because of the sound quality, the fit, and the price. While the mic does still have a few issues, it's still a great improvement in sound quality to the point where I can finally have a normal back & forth conversation in the car, and that is vital. The fit's comfortable, and the unit is very light and small which I dig. The usability issue can be a little frustrating at times, but if you remain mindful, it's a minor inconvenience at worst (heck, sometimes I actually WANT to redial, so there it's helpful). There is no perfect bluetooth, but for the price, I haven't found anything better in size, fit, or sound than the Samsung WEP410.