I'm sure these are existing and ongoing problems. I think I've mentioned in other threads that the biggest problem with shared web hosting is the fact that it's shared. The other people on your server have the capability to write their site such that at certain traffic levels, your server grinds to a halt.
I think Dreamhost tends to be pretty lenient on you if your site is inefficient and is causing problems for your server. Many hosts will just cancel your account or immediately "throttle" you for one infraction. With Dreamhost, as long as you're not paralyzing the server, they'll give you a chance to fix the site yourself before turning you off.
But this forbearance causes problems of its own. It means that all the other people on the server have to live with the impact of your site on server performance until you get it fixed.
Anyway, the other aspect of this is that I've found that people complain about every other web host at the same levels. Well, I suspect that they complain about Dreamhost more because Dreamhost is transparent about their problems so people know about issues more than at other hosts and can more easily point fingers and ridicule them for their mistakes. Of course, this is why I love Dreamhost.
In the past year, I've had three outages - one due to DoS, one to a problem with a file server, and one to a bad neighbor. I somehow missed out on last year's DNS issue.
You can probably avoid most DoS issues by going with a small, independent hosting provider. You can probably avoid NFS issues by going with a provider that doesn't use a SAN - though you'd either be paying more for extra filesystem redundancy or taking the unknown risk of not having a high availability filesystem (and only having backups).
I've had good ticket responsiveness. Then again, I write up good tickets.
Well, Dreamhost has their oft-mentioned 97-day money back guarantee if you pay using a credit card or Google Checkout.
My personal opnion about selecting a web host is that my ability to do what I need easily and expediently is the most important criterion in my selection of a web host. Content and creativity are king. As long as I have the time and freedom to create the site to the best of my ability, the web host that maximizes this ability is the one that I will pick.
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