I bought this headset to allow me to listen to podcasts on my morning commute whilst avoiding the tangle of wires and also allowing the option to make and receive phone calls. They were great value and worked straight out of the box, here is a little summary of what I thought was good and maybe slightly bad:
Good: Light, comfortable, batteries last a long time, easy to pair, include a battery indicator on the iPhone with no downloads or updates needed, easy to hear what's going on around you, don't leak too much sound, just about loud enough in a very noisy street, great quality on podcasts.
Slightly Bad: Bluetooth link to the iPhone is not strong, can get some breakdown when moved away or you cover the phone with your hand but is fine in most cases, no real sound isolation if you want to get away from things but this can be a positive as I like to hear when walking, look a little bit weird and can be slightly uncomfortable if you try to lean back on the cord as it's quite stiff.
I have not had a chance to test them as a phone headset for more than a couple of calls but they worked fine, maybe just a little quiet but will add to this if I get any negative results.
Overall I think they are the best bluetooth headphones I have had but it does depend on what you want them for. They excel in many areas but are less good in others albeit only minor niggles in my view. I can thoroughly recommend them. My phone is an iPhone 4GS.