Hard to beat solder.....at least every thing that`s sorta permanent.. The snap together connectors....there`s a bunch of different brands.. study them pretty good before you choose and stay with one type. New stuff that I haven`t dealt with is probably out there that may be pretty good stuff.
The one thing I`ve practiced for years is on a metal to metal connector is to use a tiny amount of copper based anti sieze called C5-A ( Ground up copper in a grease base )...permatex brand I believe, to coat the connection. I use it on everything from battery posts to blade connectors. I don't use it on engine type multi pin plugs ( I learned the hard way)....can cross jump to the other pins and those connectors usually don`t cause trouble anyway.
The c5-a can be a little messy but it just takes a tiny tiny amount to keep the air and moisture out that causes most connection problems on boat stuff. The copper helps conduction of current. They also make a graphite based antisieze that works too but I prefer the copper based( color tells you which kind you have). Just make sure to wipe the excess of real good.