I think all companies make good and bad engines....just depends on which one on the line you end up with. After BRP bought out OMC their engines got WAY better...the old ficht engines I've been told to steer clear from...One of the best they ever built was the early 90's intruder and faststrike. They were beasts....unless you took them in for service and got detuned! There were a few years in there though that OMC had a bad time...then BRP brought them back with the etecs...I've heard good things about them...I've heard good things about optis...but I've heard the best about the 4 stroke yammies, hondas, suzukis and such. When my GT150 Johnnyrude goes south I hope to be in a posistion to get a 4stroker on my Ranger.
Mercury has also been known for high performance engines....you rarely see high performance upgrades or forums for the johnnyrudes...now I do not know about the newer ones. I was always told that for the recreational user the johnnyrudes were better and for performance get a merc. Thats also why you see more questions and problems on forums for mercs (older) because of their performance characteristics many get pushed harder. Most of what I know is about 90's and pervious engines....carbed engines. Thats where my info comes from...can't tell you about newer ones...all I know is I hear really good stuff about the 4strokers I mentioned earlier...I really want a yammie myself. :D
"But if serving the Lord seems undesirable to you, then choose for yourselves this day whom you will serve, whether the gods your ancestors served beyond the Euphrates, or the gods of the Amorites, in whose land you are living. But as for me and my household, we will serve the Lord.” Joshua 25:15