I did use it a few times for routine calls to the coastguard a few years ago when i first got it. It is easier just to use ch 16 usually so just stopped doing it.
On sunday I had the manual out at the beginning of the run just in case anybody tried to call me as I couldn't remember the procedure for answering a call!
Quite a bit. Find it very handy for getting hold of other boats that I am working with/trying to find - the ringing is a lot more noticeable than you trying to call up repeatedly on channel 16.