I have HP, two 22 inch monitors. Good quality. Good colors. Never had any issues. While having these two monitors, I have also used several iMacs, for two different companies designing ads/graphics. Going to work for 8hrs working on an iMac, then coming home to use my computer I can tell you, I saw no color difference, no quality difference between the two displays. Heck, I didn't even see a performance difference.
What I am getting at is, buying a iMac based on display compare to a monitor for a PC is a waste of money. My monitors at this point are probably reaching 8yrs old. For technology they should be replaced. However, there are no hot pixels, in great condition, I bought a good graphics card and I calibrate the monitors.
I give HP a 10.
I have also owned Sony and Samsung monitors. This was years ago. At the time, the Sony monitor would have been rated a 12. So I would hope Sony only got better with times on their quality. At the time I would rate Samsung, 8/9/10.. this is depending on the model you get.
In the end, go to a store like Best Buy or the such, where they have the monitors on display and look at them. Stand close enough that would be the same distance as if the monitor was on your desk. Don't compare the quality far away, as if you were watching tv. Compare close up, as if you were to actually use it. Buy what is within your price range and what looks good to you.
