Dear Skrat,
Oh my! I feel for you. This is a difficult and scary situation. I'm afraid I don't have any experience with any RTCs, so I can't help you with your search. But you have come to the right place for information and reviews about that.

I know I've read that some parents have had experience with both those RTCs. I hope someone who has sent their loved one there will respond in time to help you decide.
BPD dd17 is refusing to see a new P (long story about what happened with her P of 3 years) and yesterday said she would no longer see her T where she was doing DBT work. In addition, she is not doing her summer classes (which will affect her graduating on time), not doing acupuncture which she loved and today said she doesn't want to take drum lessons anymore. Her emotions and anger are so all over the place.
-sigh- This is a big concern! It's good you're getting her into an RTC. We're dealing with very similar behavior from my BPDD17 also. All she can think about is moving across the country to live with her BF, and she doesn't want to continue with therapy or meds, or school (she got her GED and has been at a J.C.). She is absolutely convinced that moving away and "having a fresh start" by living with her BF will solve all her problems. We're very concerned, but she'll be 18 in a few months, so we know we can't stop her and she won't listen to reason.
Please let us know which place you decide upon and check in with us whenever you can. We're here to support you through this!