It's about the pool software that the pool operator has put on those servers, that software is in beta.
I don't understand why he would put beta software on the other servers ? What would the reason be ? It would be nice if it could automatically redirect to the default server when issues arise.
I believe it's in beta stage because it contains additional procedures to run the pool on multiple sites.
It's called beta for a reason: if one doesn't want to experiment, he can just stick to the middlecoin.com main site.