I'm looking to upgrade at least 1 of my 17" basic Acer monitors to something that's IPS. Since I'm a hobbyist, I can't justify the expense of an Eizo or the like. I'm more in the $500 USD and below range. Depending on the price, I may even be able to swing 2 to continue my multiple monitor display. The monitors that I'm considering are below..
Dell UltraSharp U2410 24" Widescreen LCD Monitor
Discontinued, difficult to calibrate even with a hardware calibrator, wide gamut which can be a handful for a hobbyist who is not up to speed on color management issues and who may not use software that is fully color managed.
Dell UltraSharp U2312HM 23" LED Monitor
Too bright at minimum Brightness (0%) for use in moderately dark to pitch black rooms.
HP ZR2440w 24.0" LED Backlit IPS Monitor
A good choice - similar to U2412M.
ASUS MX279H 27" Widescreen LED Backlit LCD Monitor
1920x1080 resolution - pixels will be noticeable if you use this on a desktop and sit within 24" to 30" like most people. Might be good for you if you have eyesight issues (native fonts appear larger).
ASUS MX239H 23" Widescreen LED Backlit IPS Monitor
Unknown to me.
I've heard great things about Dell's UltraSharp displays. With technology going towards LED, is the 23" LED version a worthwhile investment compared to the 24" LCD that's done so well?
Be careful. An LED monitor is a LCD with a LED lit back light. Just because a monitor has that new fangled LED back light does not mean it is superior for image editing. The one area where they are clearly superior is that, as compared to the legacy CCFL back lights, they are much more power efficient and they turn on at almost full brightness where the CCFL's came up to full brightness after about 20 to 30 minutes.
There are all kinds of potential issues with LED back lights including gamut coverage and uniformity.
Up until recently a white LED could only provide coverage of about 94 to 96% of the sRGB color space where in the past standard CCFL's could go to 96-98% typically (a wide gamut CCFL was used for 100% AdobeRGB coverage). But LED back lights in laptops often only provide about 67% coverage of the sRGB space. Recently, as in the past 4 months, a new generation of LED back lights has come to market that provides about 98 to 99% coverage of the sRGB color space. These can be found in the new Dell U2713HM and HP ZR2740 v2. A new wide gamut GB-LED back light providing near 100% coverage of the sRGB and AdobeRGB color spaces is in the Dell U2413 and U3014.
With low end LED back lit monitors you will often find issues with edge bleed, flash lighting (a form of edge bleed where it looks like a flash light is shining in the corner of the monitor), and panel uniformity. CCFL back lights also had issues with panel uniformity so LED has not proven to be a cure-all.
Furthermore, there is an issue with lowering the brightness on a LED back lit monitor. Some/most manufacturers accomplish this via a technique that rapidly turns the LED's on and off, known as PWM or Pulse Width Modulation. Even though the frequency of this is quite high, some people can perceive a flicker from the screen when the Brightness is lowered substantially as is commonly the case with most monitors used in image editing.
I've also heard and read good things on HP and ASUS.
HP's ZR line is well respected though some models have had weakness's (the old ZR24w was too bright fro editing in a very dark room). ASUS has been hit and miss. I encourage you to read the reviews on these two sites.
(newer reviews are on the German language side)