i have both the Dell U2311H and 2209WA. Both IPS screens are good. My personal opinion is that the 2311 has better contrast and the 2209 has more vibrant colors.
Both monitors are way too bright at default setting. I have to wear sunglasses.
I adjust to something like 20%.
The 2209 seem to have a more natural aspect ratio for viewing photos. It has a lower reso than the 2311, however. The 2311 has a shorter screen height physically than the 2209.
I am pleased with both monitors but i would think the 2209 is better for photo editing.