Samsung C32F351 Response Time Settings:
Both monitors Fastest Response Time setting is useless due to excessive amounts of overshoot ghosting, and both monitors suffer from mild to medium (S32F351) or medium to excessive (C32F351) amounts of overshoot ghosting when the default Faster setting is used. The S32F351 suffers from significantly less overshoot ghosting, as well as significantly less color streaking and smearing of dark colors and shades such as browns and greys.
The curved C32F351's overdrive performance is poor regardless of which setting is used since the Normal setting suffers from very obvious smearing of dark colors and shades (black, brown and grey), and because the Faster setting suffers from very obvious overshoot ghosting.
The non-curved S32F351 is actually a decent 60hz gaming monitor since the Faster response time setting only suffers from obvious overshoot on a few transitions such as light blew and white during the daytime skies of some of the
Overwatch maps like Illios.
The Faster setting is almost free from the typical VA panel color smearing, as is the Normal Response Time setting, though the pixel response times do slow down a bit resulting in marginally more color streaking, but the Normal setting is still good and may be the preferred setting to those who can't stand overshoot ghosting.
While it is unrealistic to expect AHVA/IPS/PLS pixel response times from a VA panel it seems Samsung is closer to minimizing the difference with the S32F351 which comes very close to offering 60hz AHVA/IPS/PLS pixel response times and eliminating VA smearing. The most pronounced overshoot ghosting I saw was on light blue and white when viewing content like the blue sky with white clouds on the Overwatch map Illios, and when panning the camera while looking at the Traveler in the Tower of Destiny during the day. Quite a few other budget 1080p IPS panels also exhibit similar amounts of overshoot ghosting unless their overdrive is also set to the lowest setting or turned off.
Those who want a VA panel without obvious smearing and overshoot will likely be satisfied with the Samsung S32F351 while the C32F391 offers below average pixel response time performance, and is easily the worst monitor I've tested in years.