Got my monitor this weekend. (Dell U2413)
Sitting it next to the monitor I've been using for 5+ years, which is a TN panel (BenQ G2400WD or something), I'm only noticing the color temperature is different. Outside of that, the colors are not blowing me away. Videos usually look worse on my new U2413 (This is partly due to using different color spaces, at first, and color temperatures). I'll say that the IPS glow is very noticeable on darker scenes in videos or in games with dark areas. It's extremely apparent and annoying.

Some of the photos actually look better on my old monitor even when both monitors are in sRGB mode. This is comparing photos straight out of the camera too. I bought an i1display pro to calibrate my displays. So, any discrepancies I am seeing will, hopefully, go away when that arrives. I'm thinking that right now that everything is also just being shown with warmer imaging. It could also be that since I am using warm white fluorescent lights in my room that my old warm G2400WD display is looking better because of ambient lighting as well. It could be that the difference between the Dell's cooler (likely more accurate) color temperature is too much with the current fluorescent lights. Maybe I'll get different bulbs in the room. The screen is also crazy bright in my room above 15 brightness. (It burns out retinas bright!)