There’s no meditation in CorePower; some teachers do start you off while you’re warming up with a phrase or quote or concept to think about but you’re completely free to ignore it. It’s physical, not spiritual. Don’t worry, meditation drives me batty too 
They are not slow paced, at all (except for a specialty class they call CoreRestore, which is like yin yoga).
Generally speaking, each studio offers 5 types of classes -
CorePower 1 (it’s the beginner level, but still intense vinyasa flow - you are moving the entire time)
CorePower 2 (higher level version, more advanced moves)
Yoga Sculpt (yoga with weights. Hard! You are soaked afterwards!)
Hot Power Fusion (this is super heated, similar to Bikram)
Ryder (spin class)
It’s all very body weight and core oriented. Per my Fitbit, I burn somewhere in the range of 225-250 calories for a C1.
They give you cool lemon lavender cloths on your forehead at the end of every session except for spin. Sold 
I advise starting out with a CP1. The friend who took me started me out on a CP2 and I though I was going to die!
I do a lot of C1s but mix it up by adding CP2 and Sculpt every now and then. HPF is too hot for me.
I have generally been pleased with all the instructors; there are certain ones I prefer but there have been none I thought were bad. IMO, they explain the moves clearly, they correct form, and they proactively provide modifications if you can’t do something, or a harder option if you want a bit more. No pressure if you can’t do something.
Each instructor does his/her own music so it can be anything from sitar/traditional Indian to country to pop / rock.
You can buy packages of x sessions or monthly unlimited membership (I have the latter). Your membership is good in any studio in the country which is nice. I actually rotate between several different studios in my area depending on my schedule, errands, etc. They are Starbucks-y insofar as you’ll get a similar experience wherever you go. This is a feature, not a bug, from my standpoint. You can book classes through their app or Mindbody.
They make their money through teacher training and retail more so than memberships, but they don’t really push it. However, they did have a cute Kate Spade / Beyond Yoga collaboration and a jacket made its way home with me :-).
Let me know if you have other questions!