From my experience, biggest weakness about memcache is that client libraries for it are crappy or at least the one for java. Otherwise it seems like it is great

From my experience, biggest weakness about memcache is that client libraries for it are crappy or at least the one for java. Otherwise it seems like it is great for what it is (a memory cache). Redis rides a bit on its hype IMO, and I see that sometimes it is not used correctly.