I don't like the Elasticache offering of Redis at all. It is severely limited if you are not just using Redis as a cache. There is no way to scale up/down the size of the node without putting it down(this is possible if you run it on EC2 as well as you have access to commands related to replication that are not allowed on Elasticache). We have had master restarting instead of failing over to slave and in the process coming back with no data. Even the snapshot is only taken once in a day.
