Fox engines aren't for everyone, but when you do figure them out, and have them running good, they tend to outlast everything else except for Enya engines.
I am still flying a few airplanes with FOX engines on them. A 24 year old 40 size low wing plane with a FOX 45 on it. It is due to be installed on a new plane as that old plane is getting pretty worn out now. One of my 15's is on a new 15 size sport 3D plane. It has been on two different airplanes since I first got it like 20 years ago. I have a old Eagle 60 baffle port engine on a new Extra 500 scale plane. It still runs good too. My 74 was on a Japanese Zero that died years ago, I need to stick it on the front of something again. I happen to have old FOX 36 RC currently on a foamie Cessna 172 that is still going strong. It just won't wear out.