This is of course determined by the needs of your application. It is important how many of your estimated instant users in your application will be. Also, the features of the application will affect the architecture of the application. For example, if the message data would be processed on the server, I would prefer a distributed server solution such as akka actor with the rabbitmq cluster. I would definitely use Redis. Both technologies are incomparable lanes. Redis is a database and its purpose is to process data from a different memory with the memory used by the code running on the server. Rabbit is a messaging queue system. It contributes to the architecture in a different dimension. Performance and stability are keywords.
I'm curious to find out why many people decide to compare seemingly disparate technologies such Redis and RabbitMQ? Is there some sort of esoteric ninja trickery behind this?