So if you need to reach 10mi - you should go fixed mount with a mast head antenna. If you are confortable with 6 (assumes the other guy is on a handheld 6ft above water as well) then a handheld will work.
I'd recommend DSC, but be aware you need to hook up a GPS signal to it. Most seem to be NMEA 0183. But the GPS industry is going towards NMEA 2000. A conversion between the 2 can rival the cost of the GPS itself. If you have a handheld GPS in the cockpit it can be inconvenient to connect to your VHF depending on mounting location of the VHF.
I have a fixed and handheld as a backup.
I have a Stamdard Horizon fixed GX2100 with DSC and AIS RX (not much use to you on the lake). It is installed below with a remote RAM mic at the helm. I also have a SH HX850 handheld which has DSC with a built in GPS. They have a new handheld 851? that actually lets you use the GPS for waypoints etc. vs mine which simply displays position and makes it available for DSC.
SH and ICom consitantly rate well in practical sailor etc. tests of peformance.
Other features such as scanning etc. depend on your preference