I have to start by saying I did not expect to really like these headphones, I typically don't like in the ear buds. Previously I never thought they were comfortable. And I've kept trying them (Apple, Klipsch, Sennheiser, Bose, LT and Sony to just to name a few) looking for the right combination of comfort, sound quality and usability (they need to have a mic sport so I can use them with a cell phone). Call me insane for doing the same thing over and over expecting different results, well it was over and over with different products; very few of them I actually bothered to return. Most were in the $100-250 range.
Full disclosure, the first pair of Jaybirds I acquired had a problem, the right earphone worked fine but the left one dropped in and out (lost all volume) over and over certainly not to be expected. I contacted their customer service, promptly got a real person late Friday afternoon, they had me quickly try a few things, concurred there was a defect, the sent me a return label right then, and they told me they'd try to expedite a replacement. About a week later they arrived, and the new set immediately worked without issue. Yea, but they handled the situation as well as possible and are to be commended.
The earbuds paired easily with my iPhone, they show up as Jaybird RUN listed twice, as soon as you connect one the other connects at the same time - easy. Tried the same from my notebook, no problems.
The earbuds come with 5 different silicon ear tips to customize the fit; they also come with 3 different silicon "fingers" which help hold the earbud in the ear, even when exercising - yes they really stay in place. At first I thought the default eartip was fine, but after using them for about 3hrs I decided to investigate other fits. I ended up preferring a less solid fit, a smaller size with thin flaps at the side, once in place they offered me a much better bass response and I found them surprisingly comfortable for longer listening periods.
Now battery life, on a single charge I found that I'd get a little more than 3 hours before a pleasant voice told me I was at 20% battery life, which was about right, as just after 4 hrs listening the same little voice told me I was low on battery life. Great, it was lunch time, I returned the earbuds the their charging case (a black pill shaped case a little smaller than 2 ping pong balls (but heavier)); the case connects via a micro USB to USB connector (9" cable) (Glad to see Std Connectors) for charging. But the case also contains back up batteries to fully charge the earbuds (once) without additional power. The ear buds charged to 100% in under 20 minutes (little voice told me they were fully charged when they again pair with my iPhone.) 2 Led's on the exterior of the case flash to indicate the changing status of the earbuds, and another shows the status of the cases built in battery - simple, easy to figure out - blinking = charging, steady = done.
Finally, how do they sound - GREAT; a very nice soundfield, with really nice tight highs a smooth mid range, outstanding vocals and pretty good bass. The bass is not going to blow you away, but it matches nicely with the timbre of the earbuds. As I said earlier getting the right fit will effect how they sound; getting a tight enough fit improves the base greatly. And yes they weigh a little bit, but they stay in place in your ear, with no cords or anything else hanging down out of your ear. You can quickly shake you head from side to side, jump up and down and they stay place. Even when exercising in a tread mill or elliptical they felt good, even when sweating significantly they stayed put and did not move around my ear.
The last thing I tried was the earbuds as speaker phone with my I phone. Here I had some difficulties, the volume level when using the phone was MUCH lower than when listening to music, I had to increase the volume quite a bit to hear the call; in addition the volume from the mic did not pick up my voice as well as hoped, I was testing an an area with some constant background noise (fans) and the people I tried talking with had a hard time hearing me, when I move into my "phone booth" (a quieter room) there was less of a problem, but callers still thought I did not sound as full/rich as I did directly on my phone. In talking to several other they described my voice over the earbuds as "tinny" and missing "depth". Although not unusable, it was disappointing, being told I did not sound like myself. Well there goes one star. Other than that I was very impressed with these earbuds, for music and "running around" they work great, better, more comfortable than anything else I've tried. To use on the phone they don't currently quite cut it.
I almost forgot, there is an "app for them" the best feature allows your to change the tone of the earbuds via a 5 band parametric equalizer; they offer several presets, but I made a custom setting I liked much better. There custom equalizer has the sophistication that I've seen when customizing high end hearing aids, quite cool. The app also allows you to share play list info (Spotify), to find your earbuds and see the battery status. It's well done and I can see it getting better.... a nice 'surprise' bonus.