Thanks andrewf and Finglor. I've seen similar questions on servefault, specifically the 3-second /ipv6 thing, but I wasn't sure how good my memory was since I haven't logged anything. I was sure that <100 ms was the norm, but I didn't have any evidence.
Personally, I'm not too concerned with it being so slow. I'm more concerned that there might be a problem, as there was in the past which Dreamhost initially acknowledged, accepted blame, and promised they were working on it. But it seems to me that there may still be a problem and I'd like them to know about it. The problem is, the last time I tried to inform them that a problem may still exist, they turned around and blamed me for the problem which I'm pretty sure it is not.
At least knowing what ballpark figures to expect, I can try to inform them yet again that there might be something they may want to look into.