Here's my experience. I'm a 42-year-old female, very short (just under 5 feet tall). About 10 pounds overweight at the first box; about 15 pounds overweight at the second.
I tried the first box two years ago; it's about 20 minutes from my house. I did the on-ramp sessions and rocked that for the two weeks. But then for the month that I did classes, I felt overwhelmed. Very crowded classes, so I didn't get a lot of individual attention. I felt a lot of pressure to Do! The! Reps! To be fair, that could have been how I perceived it. I was very insecure. My form was shoddy, and I wound up yanking something in my back. I didn't return.
I tried the second box last summer; it's about 15 minutes from my house. For the first month, I felt very encouraged - I wasn't the oldest person there, and while I was slow and had light weights (my best ever deadlift was 105 pounds; at the time, I weighed 110), I felt encouraged to do my best. But during the second month, I started feeling the Come! On! pressure. I came to realize that A) I hate the team race mentality and B) I strongly prefer one-on-one sessions.
I'm recovering from ACL surgery (tore it during taekwondo, sigh; 69 days before I hopefully get the all clear to return to TKD, which I miss terribly), so weightlifting hasn't been on the agenda. I'm going to try a bodyweight program, along with continuing my Couch To 5K program (building my endurance to return to TKD, and hey: sprints!). I may contact the owner of the second box and see if she does personal training. But if the bodyweight/HIIT sprint combo works, then I won't bother.