OK, I haven't had it done, but have 2 friends that have.
Scarring is minimal. Initially, it hurts like hell, but it's major surgery. Afterwards both women were much happier with themselves.
One thing to tell you surgeon though is whether or not you want to breasfeed your children (and yes, it is possible). This will change the way they approach the surgery - making sure to avoid cutting too many ducts and related vascular systems. One of the women I mentioned was finally sucessful in exclusively breastfeeding her 3rd child, who is now 20 months old, after a long struggle to find support and education of BFAR (breastfeeding after reduction).
There is some great pre-reduction surgery information on this site:
http://www.bfar.org/. Check it out.