Samsung and Viewsonic are both great monitor manufacturers.
There are mixed reviews about the Samsung 755DF (the DF series in general). Some rave and some complain. I think they are high quality but some get ones that were bumped around too much during shipping or something and simply need to RMA'em.
If it was the NF series you saw, (700NF?) this is an aperture grille and so purportedly shows better and more color with greater brightness and contrast than your conventional crt. you will have the 2 ever so subtlely visible lines 1 and 2 thirds horizontally across the screen. These are the damper wires that hold the grille in place. My impression is that the technology must be superior if they are asking customers to ignore these lines. You will not notice them after a while but some do. That is, as are most things with monitors, a personal taste.
People have different eyes and so one monitor may look better to one person than another.
So the best advice is to go have a look for yourself.
Look for sharpness not only in the middle but especially in the corners - where the rays have the furthest to go, and most to bend to. Good idea to look at an image that you have seen before and therefore can guage how well the monitor is delivering how you know the image should look.
Viewsonic is good too, but more expensive. the PF and GS (GF?) series are both top notch.
Consider LG and Hitachi as well. NEC too.
Good luck.
Facebook
Twitter