I'm still a BYU fan and I recommended BYU strongly to several friends who went there (including transferring there from USAFA where I went)... But it's not the right place for everyone and wasn't for me.
BYU is a (Mormon) party school - not necessarily drugs and alcohol and sex, but an extremely strong social component with strong focus on dating and social activities. Which isn't a bad thing per se for most, but for me it was too easy to fall into that and be focused on those aspects more than academics. And I was able to get special treatment from professors there to stay above water, but I wasn't really learning or progressing. So I switched over to the Air Force Academy which has more structure and accountability.
Beyond that, I mentioned there wasn't 'necessarily' drugs and alcohol and sex... But when I was there, there actually was a lot of sex. Not just ncmo and heavy petting, but straight up sex. I was propositioned more times for sex in my two years at BYU than my 4 years at USAFA. Actually, in my 4 academy years, I was most often propositioned on my infrequent visits to BYU.
I'm not saying that's necessarily the norm (from most here it sounds like it wasn't the case for them), but at BYU it was harder to maintain morals when surrounded by people who supposedly believed the same things and didn't seem to live it. Whereas at USAFA, I was known as the Mormon kid and there was a degree of respect for my beliefs, and less effort to convince me to drink or have sex with people.
A lot of this is the same reason I don't want to raise my kids in Utah. Not only that it somewhat functions as a bubble, but that when negative elements come into that bubble, it feels more normal instead of being something external.
I'm a big fan of BYU and, having raised my kids outside of Utah, would love to send them there (and the cost is obviously great). But if I'd raised them in Utah, I'd probably want them to go somewhere out of state (which means probably not Utah either for a lot of the same reasons and others)