Lonnie: First welcome to the forum and the club. An outboard motor will last a long time if properly maintained. I have a 2006 Evenrude E-tec and it runs just as good now as it did when I first got it. I change the plugs every two years, use only Amsoil HP Injector oil, change the fuel and oil filter annualy,and wipe it down everytime I use it. As far as to which outboard is best, well thats up to the indavidual. Merc has a pretty good motor as does Evenrude, Yamaha and Honda. I prefer 2 storke over 4 stroke. 2 strokes have less moving parts to brake, but a 4 stroke is more quite unless it's an E-tec.
4 strokes require more maintenace. Oil changes, valve adjustments and some like the new Yamaha have fan belts to run the altanator just one more thing to replace.