If you can find a PLS monitor in a similar price range, it is something to consider. I've viewed several PLS monitors, and in my opinion it's basically identical to IPS (in terms of viewing angles) with slightly better black levels. Mind you, the black levels aren't as good as VA (VA has it's own problems as TN does...) but it is something to consider.
In fact, I would say that the PLS samsung S27B970D is the hands down the best 2560x1440 monitor i've ever seen. By a mile. But, I know you're not looking for a WQHD 27 incher....Anyway - IIRC, both Asus and Samsung have 24 inch PLS monitors, 8 bit, available. One advantage they have is that they used semi-glossy matte as compared to the full matte used on 2010-2012 model Dell screens, you'll find that the full matte is much thicker and text / colors will not be as vibrant as they would with semi glossy matte.
Edit: another note about Dell screens - all of their 2013 model screens are using the better semi glossy matte. That includes the 2413, 2713HM, 2713H, and u3014. All of the 2012 and prior models are using full, thick matte (which is worse). Actually, nearly all 2012 and prior IPS models use full matte, but LG is only producing semi glossy panels now. So, that's another purchasing data point for you. I think semi glossy is just way, way better. Text on white backgrounds is significantly sharper and easier to read on a semi glossy anti-reflective screen as compared to full matte.