If you don't want to read my long rambling, skip down to the pros and cons below. Also read my update below.
I previously owned a 'Samsung 226BW' for 6 years (TN panel) and had the 'HP LP2475w' briefly (H-IPS panel, instead of e-IPS like this ZR24w). My problem with the LP2475w was it's wide gamut and I wanted consistent color saturation across the entire desktop. I wanted a good looking monitor for multiple purpose, for work and entertainment. This ZR24w meets my need, it only come with a few small imperfections, but they are not bad enough so I would still recommend it.
General impressions, the good stuff:
-The monitor has a very sturdy stand. After turning the brightness down to zero (which is still bright enough), it output around 37watt which is acceptable. The monitor is very bright, but CCFL backlights are known to slowly dim as it gets more hours, so this is a good thing for the long run.
-The colors are simply stunning, combined with great contrast this monitor have very good clarity. When viewing photos and videos, the details and objects stands out, unlike most TN panels which look washed out by comparison. Watching HD videos should be a joy.
-The text is really smooth and sharp at the same time, one of the highlight of this monitor. Good for people who spend lots of time reading online. Small pixel pitch (.270mm) so you won't notice dots unless you move your eyes up close to the screen. There is a feature to adjust sharpness, but only 5 steps, which isn't enough IMO.
-The monitor is standard color gamut (not wide), so colors are not over saturated and are consistent across the whole screen. This is important as it makes the monitor more attractive to average users who don't want to mess with color profiles. Of course, if you are an artist/designer and want to work with Adobe RGB colors, you should buy a wide gamut monitor instead.
The green tint:
My previous HP LP2475w have the infamous problem that plague some IPS monitors: one side of the screen have a pinkish tint and the other side a greenish tint. Unfortunately, my ZR24w came with a slight green tint starting from the right edge of the screen disappearing toward the middle, the left side is white. I can notice the green with white and gray backgrounds. Turning down the green and calibrating the monitor can help a lot, but the green doesn't fully go away. This imperfection bothers me because I do a lot of online reading and a bit of scripts editing that usually involves white background. UPDATE: I fixed this problem using a (better) colorimeter, more info below.
There are some backlight leakage. I set the monitor to display a black screen and in a dark room took photos of the monitor using my camera with 1/4th and 1/8th second exposure to exaggerate backlight leakage. The photo shows leakage coming from the bottom left and a small bit from the rest of corners. Believe it or not, I noticed these leakages even while using the monitor in daytime when the screen background is a dark colored like black or dark brown, though not anymore if the screen is displaying brighter colors. Also, the backlight slightly dims along the very top and bottom edges of the screen.
The black level isn't great and have problem showing 'true black'. Experienced users will know what I mean when a monitor's black level is not good and instead of pure black you see kind of a 'reflective black' because of the backlight bleeds through. This creates a problem when you watch movies or play FPS video games where very dark scenes are involved, this 'reflective black' can makes it harder to pick out objects and details. Despite this, the contrast is good and the colors are accurate, it's still much better watching black and white films on this monitor than my Samsung 226BW. However, I don't think this is the best monitor to edit black and white photos (also due to a bit of 'color banding', though rarely will you notice it unless you are doing specific tests to identify the banding).
If your eyes are leveled with this monitor, the image quality will remain if you shift left and right horizontally. However, if you stand up and look down from the top-right or top-left, it loses gamma and saturation. So imagine a situation when someone is standing by your side looking down at the monitor, they would either have to bring their eyes down to the height of the monitor or step back one or two steps to see more clearly. Same problem looking up diagonally from below. This e-IPS panel has better viewing angle than TN panels, but possibly not as good as the more expensive H-IPS panels.
-Input lag: I have the Samsung 226BW which is known have very low input lag. I connect it and the ZR24w to the video card for clone view, ran a stop-watch timer software and set my camera to 1/125th second exposure time, then took photos of the two monitors. In the photos, the times displayed on the ZR24w screen are slower than the times in the 226BW for only 10 to 30 milliseconds, only rarely does it reach 40milliseconds. This is actually acceptable, my previous HP LP2475w's input lag averages higher, so HP improved with the ZR24w.
Note: Some says the "Overdrive" feature used by some manufacturers to reduce ghosting could potentially increase input lag. I tested with Overdrive on and off, in my test there doesn't seem to be a difference for the input lag time.
-Response Time: The vertical pixel response time is very good, but not as good horizontally. When watching Formula 1, onboard videos look good because it deals more with vertical motions. However, it can get blurry sometimes when cars speed very quickly horizontally across the screen. Turning on the "Overdrive" feature helps, ghosting almost completely disappeared.
-For FPS gaming, ghosting will be more noticeable especially if you have a fast video card displaying high frame rates. With Overdrive off, the ghosting made me felt like I had a few drinks. When it's turned on, ghosting is reduced and games are much more playable. To me, the difference is big so Overdrive is a must for FPS. Due to this screen having great contrast and clarity, the details stood out and I was able to pick out enemies from the distance easier, this allowed me to get better scores despite not the best response time.
This may sounds somewhat like negative review, but I'm a very sensitive user, some of the problems might not persist or as bad for other buyers. If you're interested in upgrading from TN to IPS panel monitor and don't want to deal with wide color gamut and colors profiling, then this HP ZR24w is a good upgrade. For media related tasks like gaming, photos and videos this monitor will display colors and details beautifully. It's easy on the eyes for reading texts. I bet for most people beside very hardcore gamers the display speed will be just fine.
UPDATE: I upgraded to a better colorimeter (Huey Pro). It came with a software that can apply calibrated colors across the entire desktop. Surprisingly, it eliminated the green tint to the right of the screen. Also, I think the 'standard factory calibrated colors' are not bad and isn't far from the results produced with my colorimeter, so even if you don't intend to spend extra for a colorimeter I think the default colors will still look very nice.
-Clear and detailed, accurate colors
-Smooth and sharp texts, easy to read
-Is standard color gamut (not wide) so entire desktop is not over-saturated
-10cm vertical adjustable stand that's stable, 90 degrees rotation, screen is removable from stand for mounting
-Acceptable input lag and response time ('Overdrive' feature helps reduce ghosting)
-Viewing angle is good horizontally, but not very good diagonally
-Black level isn't great and some backlight leakage
-Slight green tint on right side of screen (for the monitor I received), can be reduced by calibrating using a colorimeter
-Small amount of 'color banding', though not easily noticeable unless you do tests to look for it
PS. Mine came with no dead or hot pixels.