I have owned several Bluetooth cell phone headsets, and the PLT 510 is the best so far. It fits my ear perfectly, I can wear it for hours without noticing it, and it gives great sound. I had no problem syncing it to my iPhone, and although I haven't tried any other devices, I anticipate no problems.I only have two complaints:1. The on-off switch is very small and hard to use. I find that I have to push it with my thumbnail to make it work. If you have smaller fingers, you may have less of a problem.2. Plantronics uses a proprietary connector for charging, while other manufacturers are switching to mini or micro USB. A proprietary charging interface means one more wire to carry with me.In summary, a great purchase.