I've stayed in Benalmadena a few times but never at Easter. It is quieter than tormolinos (sp) but a much nicer resort IMO. We stayed at the sunset beach club and it was really lovely. We went in May and October and there was still lots to do and see.
I've not stayed in Benalmadena itself but I've been on a day trip there when staying in Torremolinos. It seemed nice enough though this was a few years ago, although it was quite quiet, seemed to be mostly older couples in Benalmadena compared to families with younger children in Torremolinos but if I remember rightly there are regular trains that run from Malaga down to Fuengirola and stop at both places and a few others in between so it's easy to get to different places for a change of scenery.
We usually have a week in the sun at Easter, generally Costa del Sol or the Algarve. Don't want to go as far as Canaries due to cost/length of flights just for a week. Always try to go somewhere a bit different to in the past but running out of options. What is Benalmadena like at Easter? Any resorts you would compare it to?