G-Sync and 144hz impressive, that's it.

Spoiler: I have the monitor after a whopping four hours again
packed and requested the return of Amazon.

Monitor is the next day was there, super packed,
easy to set up.

Connected to the computer, start the computer.
Direct I realized that I no calibration
with this monitor guarantees never become happy.

So, G-Sync and 144Hz set, create a color profile,
Brightness and contrast adjusted to the monitor.

After I had halfway acceptable colors, I then
Battlefield 4 times started.

G-Sync is extremely impressive. My computer creates maximum
Details about 100 FPS in the game.
Holding of jerking or tearing any track G-Sync delivers what it promises.

Unfortunately, this effect is primarily only in a handful of Play tool
Shooters as impressive.
League of Legends similar to, for example, from the bird's eye view of a
Strategy game goes this effect almost completely lost.

Other games on the other hand turn, for example, 60 Hz refresh rate
back (MechWarrior Online) and the effect is also lost largely.

That 144Hz Gaming Monitor reportedly barely motion blur or ghosting
have, I can not confirm limited.

The Ghosting is highly dependent on the "AMA Setting" (overdrive function) Monitor
from. Anything other than "High" with this function makes either pale ghosting
Effects or highly visible negative ghosting effects. Therefore, everything is different
as "high" total nonsense in my view of things.

The main reason, however, why I have returned the monitor:
The viewing angle stability.

I do not in any seating position and monitor position
(And the foot is adjustable in all possible ways!
Not been a plus in this regard) possible, a uniform image
display on the monitor. This was obvious to me while browsing the Web.
On many sites, the colors inverted in the lower quarter of the monitor.

The BenQ XL2420G manages but actually to deliver a worse picture than
my old notebook of 2007.

Because I could get for the money, two monitors with IPS panel and the G-Sync / 144Hz
not impress so pronounced than that he would make up for the other obvious defects,
I have then decided to return the monitor.

Addendum: 02/21/2015:
I have completely forgotten that the touch buttons on the monitor to react partly not or only very very difficult.
This includes the power button !! If the buttons would work just as well as near-sensor of the button lighting controls.

Summary:

Pro:
- Walk very diverse adjustable pivot function

Neutral:
- G-Sync very impressive in combination with 144Hz
- However, only in the right games

Cons:
- Miserable viewing angle stability is no longer appropriate, even for a TN panel
- Calibration necessary
- Touch buttons do not work often.