I visited the elephant orphanage together with a group in January. We had heard positive things about it, and we were really looking forward to the visit. It might have been just us who didn't know what it really was, but nevertheless, most of us where disappointed. Since we had heard "elephant orphanage" we didn't expect just to see baby elephants get fed inside fences with loads of tourists around. For me, I was more reminded of a zoo (of course I understand that the project is not like that, but I'm thinking about the experience as a tourist). I don't know if it's worth the visit - if you'd really like to see baby elephants, go check it out, but there are many other things in Nairobi that should be higher on your "attractions to visit"-list.