With email it's not a new thing at all, especially with email generated by a process running on a shared server. Email is not, and never has been, dreamhost's strong point. They are making much needed improvements tho. They have shut down the ability to spoof return addresses, that's the problem you ran into before. That practice should have been stopped back about 2001. When you think about it, why would I want someone to be able to send emails that appear to come from me! Sure it seemed to be a clever way for your contact form, but what about the malicious aspects, not to mention spam. Spoofing is how phishing emails are generated, a scammer could use that same spoofing to send official looking phishing emails!
No I do not. If you read these forums often you will find out I both defend dreamhost, as well as criticize dreamhost, quite equally actually.
Yes, I've been around somewhere around that amount of time too. For what I buy from dreamhost I'm happy with what I get for the price I pay. As far as SHARED HOSTING, I don't think you will anything better. For the price you pay dreamhost really does deliver. Bobocat points this out in this forum over and over.
In my view however, I'm not sure I would sign up for VPS or dedicated Servers with dreamhost. VPS might be OK, but they seem to have a hardware issue and it causes days, not hours, of outage when a server goes down. If I were spending more money, that would mean I had revenue producing site, if I had a revenue producing site, outages like that would not be acceptable. Especially since they are unable to fail you over to a "site temporarily unavailable" message with appropriate http response code so that you don't loose your search engine SEO rankings if the search engines bot happens to come by during the outage.
As far as dedicated goes, for the money you would spend with Dreamhost I think you can find a deal that comes with better guarantee's and support.