I've been doing CF for about 6 months now. It's different. It's got positives and negatives. It is scalable and they have "work around" - like bands for pullups.
The short high-intensity does work the body different. I'm pretty strong.
I've gained quite a bit of weight. I started losing it immediately after starting to ride again. This is not all that unusual, many people lose weight on CF, some, like me don't. I'm also a T1 diabetic, CF messes with my blood glucose badly - it's so stressful on the body that it results in the liver release glycogen. Which is good and bad.
CF coaches need very little to be called coaches - 2 hr "class" and they are a certified coach.
It is all about the testosterone (lots of women, including me do it, I just couldn't think of another word). It's very macho and lots of screaming. For example, when my former CF gym was putting together a punish board - ie if you are late you must do 50 burpees; if you don't put away your equipment, you must do 50 burpees... I suggest a punishment for swearing and was scoffed at - the F-word and the like is an important part of CF! My BF loves CF and this old gym, people stay around after their workouts to yell at people doing workouts... it's all militaristic shouting in a supportive way.
Form goes away when power and speed are all that is emphasized, and when the coaches really don't know that much, you could really hurt yourself.
I switched gyms for 2 reasons, the gym I go to now posts the daily workouts - and even though I've done most of the exercises multiple times, I always look them up on youtube to make sure I understand the form. The old gym didn't post the workouts so this couldn't be done.
The second reason is, my new CF gym has a coach that used to be in the Marines, where he was a CF coach. He's amazing. Thanks to him, I am doing full-height box jumps (20"), and my squat form is improving.
I think CF is great. I think it is potentially even more dangerous than many forms of workouts.