The 525 is a much better unit than the one I had. Mine sounded like crap, barely understandable voices, the mic was horrible and people had a tough time making out my voice, and the wireless RAM mic was abysmal to use as it had a nasty delay. I also despised the fact that the wireless mic did not adjust the volume on the base unit. Because of its poor clarity I had to install a cockpit speaker just to be able to hear the VHF clearly.

The SH will allow me to control the volume of a cockpit speaker via the remote mic. Yee haw!!! I used my hand held instead when I owned the Uniden. Uniden claimed they could fix my delay issue but when I got the wireless unit back it was still just as bad. I have had the best luck with ICOM but decided to take a gamble on this Standard Horizon because of the remote speker volume control and AIS. I certainly hope that it won't't be worse than my Uniden. In the fog I take VHF clarity as one of my most important features of a VHF, hence the cockpit mounted 5.5 inch speaker.

I have used a 525 and thought it was a decent unit compared to the one I had. If anyone wants it, with the mic, I'll let it go real cheap..;)