i had that dilema earlier this week.
Brought the G2420HDBL, the only difference i could really see was the HDMI over DVI input, but then found out picture quality is same, the HDMI carries sound, and i have a decent set of speakers, so G2420HDBL all the way.
Had this beauty for a day now, and ive not regretted it.

It's a TN panel, so there will be a slight difference in shade for a given colour at the top vs. bottom of the screen. From what people have said it is at the level expected of a TN panel - I realise some are particularly bad and this effect as very noticeable. What is your current monitor?

ive not noticed any difference with colours from top to bottom personally, and ive had a look for it being as u mentioned it. Colour seems ok, but then i dont normally look for this sort of thing. now on my thrid night with this, still enjoying it.