My personal experience from 6 months of support at DreamHost doesn't agree with most of what I've read here - I've always had a response AND resolution within 24 hours and usually get some kind of email response within a couple of hours - often with resolution especially if its a problem (no email, site issues etc) vs. a question, suggestion.
Since I joined they maxed out the bandwidth and storage to the point where its a non issue for me. The biggest deal was unlimited domains though. That has saved me tons!
The only real negative I find is spam filtering - although spam assassin is used, and you can run it manually yourself via a procmail filter, I think it could be a lot nicer. My ISP has a great set up and configuration UI for Spam Assassin so it can be done.
Also for many the confusion between ids for email boxes, real shell and ftp users, and giving access to sites and FTP directories can be confusing and too awkward for them. Stuff like having to choose a user name unique to not just your domain but the entire DreamHost user space (or some subset thereof) can be irritating - but not as hard as trying to find a user name on Yahoo, GMail or AOL! Yes there are simpler interfaces available elsewhere but it just doesn't fit with how DreamHost's user management works - they have a much more direct mapping to Unix users than anyone else. But really its a minor inconvenience compared to all the benefits.
Overall two thumbs, two big toes and a whole bunch of other digits up from me, minor warts-n-all.
Here's the obligatory discount: TECHTIMEMAX for the maximum discount on all plans.
Ask yourself, who else gives you such a crazy insane referral program as DreamHost? It really doesn't take much to get yourself free hosting for life or even make money - who could ask for more?