Hi latif, welcome to Icrontic!

I've heard reports of several different 206/226BW revisions. I believe all of the original monitors were 'S' revisions, and then followed the 'A', and then others afterwards. Unfortunately, I can not comment on the performance of the others because I have never used them. The color reproduction on the 'S' panel I sampled was quite good for a TN--so were the viewing angles. As you mentioned, it is unfortunate that manufacturers change components after the initial release of a product. This is common with memory (RAM) manufacturers as well. They sometimes change the ICs in the DIMMs based on pricing and supply/availability. I think the same holds true for LCD panels.

Although the 206BW 'S' is a great monitor for every day use, I don't think you'd be too happy with it as a graphics professional. You should take a look at the SyncMaster 215TW if color accuracy is important to you. Believe it or not, the Dell E228WFP also has good color reproduction and is a less expensive TN based panel--although viewing angles are not the greatest.