Summary: When I first bought these I was really happy with them after my dog ate a pair of similarly priced headphones from another manufacturer. Whereas those ones were very bass heavy, the Klipsch produced very good and balanced sound while not sacrificing bass. While the large earbuds gave me a good fit, they kept coming off and as a result I ultimately lost them.
Pros: Balanced Noise, Comfortable, Great Sound Quality
Summary: These head phones are awesome. The noise canceling does exactly that! I ended up taking these overseas on a deployment and,just like most other head phones, the wires have gone bad and havent made them as enjoyable. I would recommend these, but be cautious, they seem to be extremely fragile.
Summary: I'd never spent more than $35 on headphones before because I never believed it could be worth it for a college student like me but I'd heard enough great things about these that I decided to buy them when my Skullcandy earbuds died prematurely...On first listen, I was speechless. My favorite songs sounded completely different in this kind of quality. I listen to a lot of metal and I was hearing intricacies in songs I didn't know were even there.
Pros: Comfortable, Compact Design, Easy To Use, Great Sound Quality
Summary: I purchased these because my dog ate my Bose earbuds. These wires feel less durable (thinner) but they have held up okay so far and I am pretty rough on my earbuds. They are definitely worth the money and the sound is very very good--better than my Bose were!
Pros: The noise isolation is fantastic. I do believe they could double as hearing protection. I put them in at work and it blocks out everything except for the piercing phone ring I turned up a foot away from me.
Conclusion: I own lots of Klipsch audio products, and the Reference S4i In-ear headphones are excellent! They deliver crisp, clear detail. Well rounded highs, mids and lows that the reference series are known for. They look nice and the controls on the cable are very functional. The Reference S4i's are well worth the purchase!