Whether it's quick or slow, on any given hour or day, depends upon _which_ nameserver your system or DNS lookup service happens to choose.

So long as they always pick the first server, it will be quick. Whenever they pick the second server, it will be slow -- things have to time-out before they fall back to the first server.

In my case, my local caching server appears to normally try the second server first, causing a five-second delay before it times out and tries the other server.

Cheers