The size of the earbud is pretty standard--it doesn't go too far in the ear and sort of rests against the opening of the ear canal. There's a rubber shell around it so it fits securely in the ear. For this reason, we didn't think the optional ear hook was necessary. Still, the ear hook is nice and flexible, and can be swiveled to fit either ear. The overall fit is pretty comfortable, but it's not something I would wear for all hours of the day. The Sun comes with an optional lanyard if you wish to hang this around your neck instead.
We tested the Iqua Sun with the RIM BlackBerry Pearl. The pairing process went smoothly, though the method is a tad unusual--you have to hold down the volume buttons to initiate the pairing process. But other than that, it was fine. Call quality was good for the most part, but we have to warn you that our callers sometimes reported slight echoes in the background, and sound quality suffered in windy environments. Also, since the Sun's earbud doesn't sit too deep in the ear, we had to crank up the volume a little in noisier surroundings. However, In quieter situations we heard each other fine.
Features of the Sun include answering, ending, and rejecting calls, last-number redial, voice-dial support, call mute, and the ability to switch calls between the phone and handset. There's also a battery status indicator, support for VoIP calls, and the ability to pair up to eight devices (You can only be connected to one at a time, though).
Of course, the big attraction of the Sun is that it has almost "infinite" standby time. It has about 12 hours of talk time with a standard charge, but Iqua says that can be theoretically extended depending on available light. At the time of this review, we have not had a lot of time with the Sun just yet, but it has so far survived a few days underneath office lights without needing to be charged. We hope to run a longer-term battery test with the Sun for a more conclusive review.