Don't dismiss the Mercury/Mariner Optimax they are also good engines. I had one from new for 7 years and it never missed a beat. To be truthful though most modern engines will give good service.
If buying second hand get as new as you can afford and more importantly than that ask to see the service records. Service records are not only useful in helping you decide whether to buy but will also when its time to move on help you sell. Do get a marine engineer or at least someone knowledgeable to look at the engine and test the compression. If new to boating and spending lots of money consider a marine surveyor to look at the boat, he may save you a fortune and in some cases get you money off for faults found
As when buying anything its a case of buyer beware cause if you don't it can hurt
Oh have fun looking and welcome to the club
Martin