Not too different from Redis at the moment, however this is straight out of a university project were we had a tight deadline and had to limit scope considerably but if you check the roadmap on the repo we want to add a lot to it.
Depending on the use case. If this is being used to reduce load on your database, then there are no noticeable differences between performance of GhostDB or redis from the clients end.
Currently we follow the memcached model so there is no replication however, remember this is straight out of university were we had to limit scope considerably and were on a tight time constraint but we aim to add data replication, consensus etc.