I'm assuming you have gotten the concepts of what DBT is and how it works from some of the other posts. If not, it would be good to become VERY familiar with its purpose and objectives. I also think it is good to be VERY familiar with, at least, the basic disfunctional behaviours we borderlines have. I say this because, when I was formally diagnosed with BPD, no one really took the time to go over the symptoms, behaviors, etc. with me. This made it difficult to understand the purpose for some of the techniques they were trying to teach me.
DBT is not easy therapy, especially when you are highly agitated.
The idea of having an instructive group session, combined with one-on-one is good. This way, you can focus your time in one-on-one sessions on perfecting/understanding the techniques taught as they relate specifically to you and your own personal difficulties.
The group sessions are a little more difficult for me, because I am highly attuned to others' "vibes," and am easily distracted. It is also difficult, at times, to see yourself reflected in the behaviours of others in the group. You WILL recognize these behaviours in yourself and some ain't pretty.

This doesn't do much in helping to boost your self-esteem initially, but at least it helps you to become more accutely aware of your own reactions to your surroundings, etc. and changes can be worked on from there.
Awareness is everything in DBT (and you will probably get sick of how "aware" you have to be all the time!). One would think being borderline would automatically suggest a hightened state of awareness, since we are so easily upset, but you'd be surprised how 'lost' we are inside our own minds most of the time.
DBT is also a long, long, long process and can be very frustrating. (I'm not helping much here now, am I?

but I am trying to be as honest about my experiences as I can for you...)
The most important thing is to have a good relationship with your one-on-one therapist. TRUST and HONESTY are a must, otherwise you are just wasting both yours and the therapists time (but I guess that can be said for any therapy).
The whole thing is highly structured; therapists are ALWAYS available to you (even after-hours); and you get tremendous support from them; more so than from any other therapy program I have been in.
Give it a whirl! It's the most successful therapy out there for borderlines, anyway, so at least you're starting at the top. Stick with it as long as you can because you won't necessarily notice the changes that are occurring until further into the treatment (not to say that you won't experience some changes immediately).
It's a long process, but worth it - even if you only learn a few new techniques to help cope - it is still worth it!
Let me know what you think of DBT if you go.