Like the title says ...

Handheld or Fixed Mount?
What brand? model?
Where to buy?

Thanks.

Check these guys out.
www.consumersmarine.com

I have a handheld and fixed. The fixed has a lot more range but it won't do any good at the bottom of the ocean with me floating on top so I have a waterproof handheld also. I've never had to use either "knock on wood"

Icom M1 handheld in the "you touch that bag I'll break your arms" overboard bag, and Icom in the dash...