I personally say boma, that is where i have made my september PS. From what ihear Boma is a little more family oriented, a little noisier, and people are less likely to stare if your children get a little raucous.
I have a VERY active 2 and 1/2 year old, and there have been times where i have left restaurants with out eating because my son was so loud he was disturbing other diners. It is my personal feeling that everyone is entitled to enjoy thier dinner without screaming misbehaving kids. A lot of people would diagree with me, but I would hate to have the tables turned around and have my meal ruined because of someone else's child.
I have heard of people bringing their young kids to Jiko however, so i guess it also depends on how your kids are.Some are quieter than others, i i would think that if your kids are quiet and generally well behaved, you could probably try Jiko. But before you make any PS's , look at Jiko's menu and see if ther are things your child would eat.
Hope this helps,
Sherrie