I thought the app was good. You can do timed runs, and the app will track your current heart-rate as well as your average heart-rate over the the course of a workout. It saves your history, updates your distance and pace (GPS must be activated on your phone) with intermittent voice prompts, and includes some built-in tests and a music player that allows you to tap into your music library.
Alternatively you can use a music service such as Spotify while the Jabra app is running (the voice "coach" prompts will lower the volume of your music but not pause it). As I said, you can also use the headphone with other fitness apps like Nike+, Endomondo and RunKeeper. The heart-rate monitor works with a lot of those fitness apps but not necessarily all of them (I got it to work with RunKeeper and Endomondo just fine).
As I said, the app's voice coach intermittently chimes in with the total time of your workout, current heart rate, and average heart rate. You can also tap the button on the left earpiece at any time to get that information.
If you can get a tight seal, the sound quality is pretty decent, though I wouldn't say these offer fantastic sound. They're a little bright and you do lose quite a bit of bass if you don't get a tight seal. They also have trouble handling more complicated songs with a lot instruments and frequencies thrown at them at once (it had a really hard time with Vampire Weekend's "Diane Young" track, for example).
For casual listening while you're working out, they do a good job, but as a said, a tight seal is crucial to maximizing sound quality, and I suspect that some people will think these sound very good while others may be underwhelmed. If you're working out hard, that tight seal can be hard to maintain.
Both the Beats PowerBeats2 Wireless and Plantronics BackBeat Fit are designed to have a looser fit and let some ambient sound in for safety reasons. These Jabras don't seem to be meant to be worn that way, but you can choose a smaller eartip and let more sound in so you can hear traffic while running or biking outside. But sound quality will suffer a bit.
It's worth mentioning that if you fiddle around with the headphones and make small adjustments for comfort and fit, the heart-rate monitor may lose your pulse and you'll get a voice prompt telling you you so. (Side note: As I was writing this sentence I got a voice prompt saying that my heart rate was 61 and that my average heart-rate was 57 and that I was in the "light" training zone.)
Jabra claims the hear-rate sensor is quite accurate. The caveat here is that most heart-rate monitors are, but my general impression is that it seems pretty accurate based at least on what my doctor measured my standing heart rate to be. (I'll update this review as we test other heart-rate monitor headphones, such as the $150 ).
Battery life is rated at around 4.5 hours. That's not great, but most of these in-ear Bluetooth headphones max out at around 5 hours, so it's within expectations.
As I said, I like this Jabra Sport Pulse headphone and think it's one of the better wireless sports headphones out there, particularly in terms of fit and features. The heart-rate monitor adds to its value and although I think it could sound better for the price, it's certainly worth considering, particularly if the idea of the built-in heart-rate monitor appeals to you.