I would say that if you are planning to use your computers underway, there is a small advantage to the SSD, but if you are planning to use them while docked or moored, you might as well just stick with the conventional drives.
In either case, make regular backups either to a medium that is waterproof or over the internet to some disk farm in the midwest.
I'm not sure what the MTBF (mean time between failures) is for both HD and SSD but it might be worth looking it up, Just google MTBF HD. I know I have HD's failing that are 3-5 yrs old all the time and they are just sitting in one place their whole life.
I can't say I've ever had a solid state memory stick fail yet.