That bit me w/their 2007wfp, which was a great monitor mostly for 1 reason: it was IPS at a great price point. Overwhelmingly positive reviews convinced me to purchase 2 of them.
Then buyers started noticing picture quality issues not described in previous positive reviews. After some research, it was found Dell had silently started shipping the 2007wfp with cheaper PVA panels, not IPS. After noticing similar issues with the 2 I purchased, I eventually confirmed they were PVA monitors. I was fairly upset.
There's a good thread on Hard Forum about all of this here.[2]
And despite very frustrated customers, Dell never acknowledged any problem. In fact, a Dell rep can be quoted: "... a 2007WFP is a 2007WFP ... It does not matter what panel is installed." [3]
I stopped buying Dell products after this experience.
[1] http://en.community.dell.com/f/3529/t/18107050.aspx