If you haven't gotten SLs yet and you're still thinking about it, I definitely think you should read this post by Renea, and think about the advice she gives on What to look for in a consultant and installation - even though she was momentarily on her high horse.(Her words!) She writes in depth about what to expect from your initial visits and installation.
(Nothin' but love for you, Renea; you know I wouldn't link you if I didn't respect what you had to say... ;-)