I'm looking at a ASUS ML239H Black 23" 5ms IPS on sale, and thinking of replacing my Acer x223w.
Both seem to be spec'd the same, but I'd be gaining >1" diagonally, and going from an aged fluorescent backlit to an LED backlit IPS. I play games occasionally, watch HD TV and movies often, and am upgrading my optical drive to BR from DVD. I know IPS monitors aren't known for their snappy response times, but both my current and the prospective monitor are clocked at 5ms response.
This response is probably too late for the sale, but I went from three of those x223w's to three ASUS ML239H's, so I am probably extremely well positioned to answer your question.
The ASUS is a lot better in most ways
- more energy efficient
- lighter
- LED lasts longer than CCFL which will degrade faster
- 23" vs. 22"
- 1080p is not only higher resolution, it's a standard one, too, so 1080p videos, TV, etc. can be played back at native resolution
- and lastly but definitely not least, even eIPS is an improvement over TN. For these monitors specifically, the TN color gamut and accuracy was meh and it simply didn't have the apparent dynamic range and color accuracy of the ASUS. I used to have a Dell IPS next to one of my x223w's and the difference was obvious.
- better viewing angles
- neither have particularly good blacks and both have some backlight bleeding, but I would not say the ASUS is any worse than the Acer
- I do not notice any worse input lag or response time that the ASUS might have; they would both be fine for non-professional gaming purposes. If you're a pro gamer, you already have a CRT, though, I'm sure.

- the cheapest 23" 1080p eIPS monitor I could find (important because with three monitors, that's TRIPLE the cost... but I don't game that much nor am I a graphics professional, so for the price I paid, I could get 3 good monitors, 1 very good monitor, or half or less of a great monitor)
The ASUS has some drawbacks
- weird, non-standard, non-VESA mount, you may have to use books or something if you want to raise the monitor. It's fine and stable but you can't ever rotate them vertically. Not that the ASUS stand was that great either.
- I got a dead pixel in one of the 4 monitors I ordered. Buy only from places with good return policies. I got zero dead pixels out of 3 Acer x223w monitors.
- some people don't like the bezel; I don't care, I don't look at the bezel when I'm gaming or multitasking
Other stuff
- I don't notice any bad anti-glare coating, I think the ML239H has a decent rep regarding that, but I don't have my monitors in an area with lots of glare, so I dunno.
Conclusion: Ditch the energy-guzzling, CCFL-backlit, heavy, 22" non-standard resolution, lower-image quality monitors now while you still can get some resale value out of them.
P.S. I posted the above prior to reading the thread. For your purposes, the ML239H will be fine. Light non-competitive gaming, media playback, websurfing, etc. aren't as demanding as, say, professional graphics editing. Some people compared the ASUS ML239H to far more expensive monitors that, imho, don't offer as good value. For me the ASUS is "good enough" quality and has great bang for the buck. (I did order just one ASUS first, to see if I liked it, then I ordered 2 more to round out my Eyefinity setup.)
Like many things in life, you get less and less the more you pay. You could pay $170 after rebate for the ASUS (like it was on sale last month), or pay DOUBLE that for a slightly better monitor like the 8-bit S-IPS/H-IPS HP/Dell monitors out there, or pay 10x or more for an Eizo. The 6-bit eIPS panel that ASUS uses is the same as the LG and BenQ one, and it does a good job of mimicking 8-bit color.
Also, the guy spouting off on calibration doesn't know how to calibrate. TFTcentral reviewed the ML239H and found it fine out of the box and good after calibration. I have a couple of photos I like to use for testing out monitors; the Acer x223w failed to display the low-contrast areas of the photo regardless of what setting I used. The ASUS ML239H, straight out of the box with no calibration, displayed the low-contrast areas just fine. Could play FPS games fine. Movies look fine on it. Good enough for me, and good for my wallet.
It's even sadder how common it is. IMO, if you don't at least own a 24" or greater IPS panel, you shouldn't be thinking of CF/SLI.
I dunno, some people care a lot about minimum framerates and stuff like that, and three 120Hz panels can be a lot to chew through for one GPU by itself.