i actually prefer the KDS Avitron AV-195TF, i run two of them on my radeon8500 retail @ 1600x1200 true colour 85Hz and they are great. i paid $300 @ BB B&M a few months ago with $50 MIR, in fact i just got the two rebates today(2months), so cost was $250x2.
i like these monitors much better that the Samsung, i run one on my test bench and its ok, but doesnt handle high resolutions @ above 75Hz and the screen isnt as sharp as my KDS.
i would definitely say that the Philips display is the weaker of the three, my business parter picked one up at OD a couple weeks ago($315) and it not quite as good IMHO. i would much prefer the Viewsonic, then KDS, then Samsung, Then Mag, THEN Philips.
its hard too find a good 19"er for 250 bucks, and you wont find a viewsonic but i would hold out for a KDS or Mag, the samsung is also nice.