I personally as well as for various business ventures, have been a customer of theirs for about a year now. When signing up I found sales to be good for the most part. While technical support has had its up and downs (as most would say), I have always been happy with the level of service, support, resources, and overall experience in respect to how much I pay per server per month.
For more specific reviews, as net suggested, please use the search function on WHT
Since March of 2006, I have pretty much all of my equipment in 3 of their datacenters.
The best way to get a hold of them, is to call them.(I have learned taht over the past months)
Create a ticket, then call them about it.
ThePlanet is my favorite right now, but I also haven't gone out and tested other providers.