The 454 has a newer Mitsubishi Diamondtron M2 tube, I would normally seriously doubt it has sharpness problems (but see my observations below after a little bit of online research) although it looks like it supports resolutions that are obviously beyond it’s capability to resolve. 1920 x 1440 @ 85 Hz On an 18 inch viewable area CRT at ~.25mm dot pitch, good luck, this isn’t a bad thing in itself. High res and fast refresh are always nice to have even if you don’t use them. The only way to really get higher res you can actually see with a CRT is to buy a bigger one or get a really small dot pitch (and they all seem to have about the same limit of approximately 1/4 mm so that’s not an option).
The point of that monitor/tube design is increased brightness.
I noticed something interesting on the Mitsubishi site:
Diamond Plus 93SB
Grille pitch 0,25 - 0.27 mm
Diamond Pro 930SB
Grille pitch 0.24 mm
Hmm… a varying apperture grille size on the 93 SB, dunno what tube is in it, both have the superbright technology which I think means it’s the Diamondtron M2.
The iiyama Pro 454 claims a dot pitch of 0.25mm on their site (not really dot pitch since the mask is really a grille on one axis but the principal is the same), other info online says .24mm but iiyama says .25mm, this would correlate with the diamondtron tube with the .25mm-.27mm grille.
Now varying aperture implies varying sharpness but a grill has to align with the phosphor on the screen so unless that varied too it would make absolutely no sense, this is all a bit strange frankly, but that’s what their site says.
Anyway, this means there is a genuine question over the sharpness of the Diamond Plus 93SB and perhaps the Iiyama Pro 454 if it has the same tube.
This is all a bit speculative but why take the chance.
Conclusion: See what price you can get for a Mitsubishi Diamond Pro 930SB.
Note that Mitsubishi honestly state that the optimal resloution for these monitors is 1280x1024 and I wouldn’t expect any better from an 18 inch viewable area on a CRT.
FWIW I have an older iiyama (Pro 502) and it is excellent, I’ve had it for years with no problems.