If you have children with you - or simply love elephants, this is a wonderful opportunity to get close to them. Undoubtedly my 13 year old daughter's favourite part of our holiday - she got to feed Lakshmi, our lovely elephant, before washing her in a bathing pool, painting her trunk and then embarking on a half hour ride through the local countryside.
Dera Amer also host elephant polo matches and have a very pleasant bar and restaurant where you can have lunch or dinner. We opted out of this as we were travelling off season and would have been the only guests there.
Altogether a much nicer option than queueing for hours to have a short sweaty ride with a lot of other tourists up to the fort at Amber.