I got one of these a few weeks back and am still absolutely loving it. I wanted a decent widescreen monitor to replace the (well regarded in its day) Viewsonic VX912 I had before, and plumped for this over the Samsung because I wanted to be able to rotate the monitor to portrait orientation. (NB. If anyone buys this, install the pivot software from HP's web site and not from the disk that comes with the monitor. Once that's installed the pivoting works automatically.)
(Talking of the pivot, the stand is magnificent, but it is a bit of a fiddle rotating the screen - you have to push panel up and back quite a way before it will rotate with catching on the underside. I'm tending to do it in the morning before I work, and I leave it there until the evening in case there's time to play some games...! And you notice that the backlight isn't absolutely even left-to-right in portrait mode, but it's not too bad, and everything is fine in landscape mode.)
I can't compare this to the SM-226BW (though I think I found a comparative review online and, though both were considered excellent, the reviewer eventually settled on the HP), but here's what I wrote after a few days of use:
"It's huge.
OK, drawbacks first - the screen is VERY reflective. It helps make photos and video footage, etc., incredibly vibrant (I'm noticing details in games that I swear were never there before), but it makes positioning important for mundane office work (though the white background of Word, say, is fine). And it's so big that I've abandoned my initial idea of using it in portrait format for work. [[see above - I persisted!]] It's huge.
However, can't fault it in any other way - it's huge, it's immersive, detailed, consistently well-lit... I could go on. The stand is incredibly stable and flexible, and it feels like it's hewn from granite. I've owned a huge array of award-winning monitors - from Sony-based CRTs to the best of the previous generation of ViewSonic TFTs - and this beats 'em all.
And did I say, it's huge...?!
Online reviews have been largely positive and mine had no dead pixels. Setting it up was about as difficult as taking a bath.
If you can find one, buy one."
So, as I say, I can't offer a detailed side-by-side comparison, but I can commend it utterly.
(If there's anything else I can contribute to this discussion, let me know.)