I use my phone for GPS if I need to, although I don't need a GPS very often, so I don't have a recommendation there.
I use a SENA SMH10 headset. I love it. I've only used it once for bike to bike communication, so I can't go in depth there, but for listening to music and taking calls it's great. I'm not a big proponent of people taking calls while on two wheels (or behind a wheel for that matter), But I take quick calls all the time, and even make some now and then. Below 50 I can do voice commands fine, above 50 and sometimes a "Call Dave" will be interpreted as a "Call Kate" or something, so I typically will only attempt to call at a stop light. No one ever believes I'm on the bike when they talk to me.
I had the charging port act up, But SENA has a 2 year warranty, and they got me fixed up in probably 10 days time from the day it left my hands.
I use an AGV Migilia Modular helmet and the old clip had to be glued to the helmet(the plastic base was to thick to fit between the shell and the foam, my old Fulmer didn't have that issue), but when they sent me a new set back they have updated the clip and now it's thin metal and will fit.
I use it all week on one charge, and it's still got juice so probably 10 hours of use and it will be dead, but you can use it while it's charging.
