In Noank, CT, I was quoted $3,000-4,000. I had it done in the Chesapeake for $1,000. This was for a 40' catamaran.
Nothing particular to look out for - it is a very gentle process and can be adjusted to leave the existing barrier coat, if present. It does leave the hull pretty smooth and you might want to lightly sand it to tooth it a bit before reapplying bottom paint.