If it is just a choice between those two, then the SAMSUNG SD390.
But, the SD390 is a glossy screen, so be warned!
However, let me give you a few things to consider.
glossy vs matte
Do you want a glossy screen or a matte screen. The glossy screens are highly reflective, but give you great colors. However, the high reflectivity can give people headaches even after just short periods of use. Thus, a lot of people chose a matte screens. Matte screens scatter the light across the surface and have a kind of "rough" finish to them. This means less shiny reflections, but the scattered light does reduce the quality of the colors a bit.
panel type
Another major factor in picture quality is panel type. Many monitors use a TN panel, which has less than idea viewing angles and can results in distorted colors at even slight angles. The alternatives are PLS and IPS type monitors. The SD390 is a PLS.
Instead, consider these alternatives:
Here are a range of IPS, PLS, MVA, PVA, and AHVA monitor around the 27" range (no TN panels):
http://www.newegg.com/Product/ProductList.aspx?Submit=Property&Subcategory=20&N=100007617%20600077224%20600030628%20600030620%20600030652%20600030631%20600487706%20600107133%20600311118%20600107132%20600012163%20600325897%20600311643%20600460747%20600439463%20600012165&IsNodeId=1&IsPowerSearch=1
So, if you need to find a matte finish screen instead of the glossy one, you can use that link and look for one that is "matte" and not glossy.
Alternative #2: gaming TN with CRT-like motion.
Another option is to get the TN panel (the one with worse viewing angle), but get one with 120Hz or 144Hz and the special CRT-like motion that gets rid of motion blurring.
This page explains it a little bit: http://www.blurbusters.com/faq/60vs120vsLB/
This page lists monitors with this feature: http://www.blurbusters.com/faq/120hz-monitors/
The first 12 monitors on that page have this special feature, but all but one use the TN panel type.
The last 3 BenQ monitors are particularly interesting, since they include a feature called "PWM-free" This means the backlight does not flicker in such a way that would make you sick like some monitors do, so they are easier on the eyes for long periods of computer use than, say, the Asus monitors on that list. (Technically, the CRT-like motion feature is nothing more that a backlight that "strobes" or flickers on and off, so I dunno if that makes this whole "PWM-free" feature a moot point if you end up just turning on the CRT flicker feature.)
A third option for gaming is G-sync, which I'll just let you read about:
http://www.blurbusters.com/gsync/preview/
If you really must have it, then there is an Asus model that you can modify or get pre-modified with this feature.