Combining a comfortable fit with excellent sound for the money, Klipsch's original Image S4 and S4i earphones have long been among our favorites here at CNET. But the one knock against them is that they just don't hold up that well over time, a criticism that seems to stem from their thin cord.
Both models come in white and black and for better or worse, the step-up S4i II has the same Apple-friendly inline remote/microphone that probably won't fully work with many Android mobile devices. But Android fans can rest easy: Klipsch does offer a non-Apple version called the Image S4A II Headphones for Android, which cost $99.
As I said, the the only real difference I see in this model is the the new flat, linguine-style cord. The bottom two-thirds of the cord is wider until it splits off into two narrower strands that connect to the buds with "L" and "R" clearly marked on the underside of the cable next to each bud, allowing you to easily tell the right and left apart. That's a small but important detail.
While the new S4 II line seems a bit more sturdy, it's not sweat-resistant like the S4i Rugged, which has a sportier look and has been toughened up with thicker rubber moldings, and an "all-weather" design. Klipsch says the Rugged's design "resists moisture and functions through extreme elements," which presumably means very hot and cold weather. I tested the Ruggeds, too, but since I was only been able to use them in milder weather, I can't vouch for how they'll hold up for skiing or just walking around the streets in the dead of winter in Minnesota -- or New York, for that matter.
The key to what makes the S4 II earphones and their predecessors so good is the angle of the earphones' post (what the eartip attaches to) and the oval shape of the silicone eartips, of which three sizes come included. The combination creates a comfortable fit and Klipsch arguably makes the best-designed silicone eartips, giving a tight seal.
For everyday walking around these earphones fit securely. Plenty of people used the original S4 and S4i for sporting use -- that's where they ran into some durability issues -- and this new model seems fine for a light workout, but I wouldn't count on them staying in while running. (I prefer Monster's iSport earphones for running).
The way you're supposed to wear them is, once the tips are in your ears, to wrap the cord over and around your ear from front to back. I never particularly liked wearing earphones like this but in theory it helps create a more secure fit and helps stabilize the cord. However, a lot of folks will simply wear them with the cord dangling from their ears.
If you're comparing these to the Ruggeds, in terms of fit there isn't a significant difference (that said, the Ruggeds don't have a flat cord). The inline remote is thinner on the S4i II, has a glossy finish, and smaller buttons, which makes it a tad more difficult to operate by feel. But that's not really a knock against it (in other words, it's fine).