These threads are useless for figuring out whats good and whats bad. We are all going to have our own anecdotes about good luck with xyz engine and bad luck with pdq engine. I had the epitome of two 'bad' engines... a turbo Mazda rotary, and the aluminum block/iron head Frankenstein monstrosity Mercruiser 3.7 four cylinder in my boat. I took the turbo rotary to an almost unheard of 125,000 trouble free miles, and I mercilessly beat the Mercruiser like a rented mule for 10+ years and rarely had an issue at all with either.
My trusty, rock solid Hondas? HAHA nope. Both the 4 cyl and the in-production for, how many years now?..... 3.5 V6 suffered flattened cam lobes, ignition issues, both leaked oil like there was no tomorrow, the 4 cyl drank more oil than gasoline, the V6 spit plugs and melted coils.... the problems just kept coming.
Both anecdotes completely opposite of the general trends. As much trouble as the Hondas were, if someone came to me and said they were considering either a 3.5 V6 Honda Pilot, or a turbo Rx7, which one would I recommend.... I would scream run away from that Rx7 as fast as they can, until they fell over and had a heart attack. Then get up, and run a whole lot more, and go buy the Pilot. Even though that goes completely against what my own experience was.
Ford straight sixes, Chrysler slant 6's, Chevy small blocks.... had them all at some point, and had nonstop issues with all of them. The older guys will tell you those engines were rock solid.
My Kia? My Mazdas with the older guy boogeyman GDI's? Literally the only nonscheduled items I've had to replace is two coils, with over 300,000 combined miles between the three.
I stand by my previous comment. These threads are useless.