I have had Mercury on every rig I've fished out of since I was a kid and don't have anything against them. They all break eventually. When I started pre-owned boat shopping last year I asked my mechanic for his opinion on the most reliable current motors because I trust him. He said if you can't get an Evinrude, get Yamaha. I ended up with Yamaha. fwiw
I had a merc (optimax)on my last boat and had a few little problems. Didn't bother me. The boat I have now has an etec. I took it in for the 300 hour service (first one) and discovered I actually had 384 hours on it. Not a single problem with the motor. It is serviced and continues to run like new.