You'll get a bunch of garbage answers here to be frank, from people who never put more than trivial load through both.

Memcache blows redis out of the water in terms of raw throughput and latency, like it's not even remotely close on modern lots of cores and big memory machines.

Redis has a more feature rich api, but has fundamentally hobbled itself on a root hash table and concurrency implementation that is circa 1990.

Give memcached a try, even if it means you implement some stuff you currently defer to redis ops. Measure it. Look at the code bases. Make up your own mind about performance and which actually makes your code simpler.