I needed a cheap and effective hands free car kit to use with my iPhone 3Gs and I think this is just about perfect. The best thing about it is that it switches on automatically when it senses movement in the car e.g. a car door opening, so it's always on and connects very reliably when you get into the car. It also switches off a short time after you've left the car which has two benefits :- 1. It drops your bluetooth connection so that if someone rings you on your mobile whilst you're in the house, the car kit isn't still in charge of the speaker output. 2. The battery lasts absolutely ages. I think I had over a month of use before I charged mine. Mind you I wouldn't take a huge number of calls through the speakerphone, but I'm still more than pleased with the battery life.
Lastly, and probably most importantly, call quality is good for both parties. The speaker volume of the unit could possibly benefit from being slightly louder, but this is only a minor issue I would have at faster motorway speeds. All in all conversations are easy to hear and I'm very pleased with this product. I've since bought my father-in-law one and he's well pleased with it for his basic Nokia phone.