Samsung makes good stuff for the price. Bought (2) 17" monitors for recent builds, customers seem really happy with them and I was please with the quality of the flat screen. Required a little setup though to get them tight around the edges.
I have the 957MB and its amazing. The 957MB has higher resolutions, and higher refresh rates then the 955, and the dot pitch might be a little better, not sure. If I were you i'd get the 957, best monitor i've ever had. I got mine from here , only took about 4 days to get it, came brand new with lots of features. Great deal!
The 950B is an ok monitor its samsungs bottom line model for the 19". I looked at thses when i bought my 950P's.
If you aren't particualr about your monitor it should be fine. you may want to look at the new MB monitors there are 3 of them for 19" and they are pretty sweet.
The 955DF flat monitor is nice also but i've heard of longevity problems with them.
I can't believe i'm giving this advice but check out the PCWorld website for their reviews -- i've sent many, many people there in the past and no one I know who has taken their recomendation has been screwed. just be careful where you buy it from.