Should I upgrade by Iiyama??

Depends:

CRTs are better at:

Motion: all LCD monitors have a motion blur during motion due to the way LCD monitors work (because they don't flicker like a CRT); this is especially troublesome in games that require lots of movement or if you just want to enjoy the eyecandy of things like ships flying around in a space RTS.


LCDs (quality ones) are better at:
Black Level: It is true that all LCD monitors leak light (some worse than others) and are thus unable to achieve 100% black. However, if you compare a quality LCD panel to a good CRT, you will actually notice that the LCD's black is blacker than the CRT due to the fact that a CRT's black is not a true black, but a color more resembling a muddy lake in the shade. This concept may not apply equally as well to a perfectly dark room, however; in such a case, a CRT might come out better.

Sharpness: All LCDs (unless the signal is bad or there's something oddly wrong) will be very sharp and will remain sharp throughout the years. This is due to the fact that each pixel is a physical object that does not change.

Reduced flicker: LCDs work in a way that causes no flicker -- except for the fact that the light in the back may flicker very, very fast. This is better for the eyes, but bad for motion as noted earlier.

Other:

Image editing: a good LCD monitor will support full 8-bit color. This means it is able to reproduce the entire range of colors, though for accuracy you may want to do hardware calibration on the monitor. However, there is another issue that arises with LCDs in regards to the finish put on the monitors surface: matte or glossy. The matte finish causes solid blocks to color to appear to have a blotchy look to it; it almost looks like the screen is covered in dust that you want to wipe off. On the other hand, you can get a glossy finish screen, but those screen types reflect light quite a bit compared to CRTs, meaning you have to deal with glare.

Viewing angle: Note: if you do image editing, this could be an issue; if you don't do image editing, this may not bother you much.
Details: Unless you get an IPS panel LCD monitor, you will suffer problems with viewing angle. What you may not know, is that even if you always face the monitor straight on, you will still be affected by viewing angle in image editing situations. In such a situation, colors at the edge of the screen may appear slightly different than the same color in the center. Supposedly, only IPS panels do not have this issue -- though I suspect once a panel get's big enough it would (because the edges would be farther away from you, and, thus, at a larger angle).

I just traded in my 19" Vision Master Pro 454 (HM903DT) for a 24" LCD. As perfect as the Diamondtron was in terms of geometry, I couldn't get enough brightness out of it w/o artifically boosting gamma via the Graphic card drivers. Odd, since it claimed a brightness of 450 nits but anyways, I don't regret the decision.

I'm a gamer and also use my workstation for movies so of course response time was a major concern, but with a modern VA or even a few select IPS panels, neither movies nor gaming [FPS - but in SP mode] presented a problem. But don't bother with a 19" LCD at this point: treat yourself to at least a 20-21" 1600x1200 if you're into graphics / imaging or a 20"+ 1680x1050 widescreen if you're into gaming and movie playback.

IMHO, 24" is the holy grail of workstation LCD monitors - 1920x1200 res and a whole lot of real estate w/o going overboard and having a TV-sized monitor sitting on your desk...

Just one more thing: ironically, I am now fighting with an overly-bright monitor when just a month ago, I was complaining about the lack of brightness of my CRT... 8O

P.S. I wouldn't necessairly go with an Iiyama LCD, though. I don't really see them being as good in the LCD field as they were in the CRT business - at least do some [more] research before you buy...!