Hi Duncan,
Sorry if this was a bit ambiguous in the review. Really that is because it is hard to define and give an absolute answer to something so subjective. This was actually addressed previously in the comments section of the review. This section is currently hidden as many of the reviews were getting too many comments and it was confusing both readers and search engines.
In short high speed blurring is always a problem on any IPS monitor. The pixels simply can't switch state quickly enough to keep up with that pace of action - and you are left with a blurry mess of conventional trailing or (as was the case with the U2312HM) a sharp-edged blur because the overdrive can't keep up. Bear in mind that this is high speed blurring.
Keeping with the examples used in the review, we said for Bad Company 2 that it is "only really when sharply turning in some of the agile vehicles that trailing become very noticeable.". If you play faster paced FPS games then depending on your own sensitivities this could become an issue when you are just running about, too. On Dirt 3 we said "there was frequent ‘blur’ of the track and environment (not related to the games motion blur effect) after even the gentlest tweak of the steering wheel" but felt that the game was "perfectly playable during the race game modes with no particularly distracting trailing getting in the way"... Except during the Gymkhana mode which is simply too fast-paced for an IPS monitor to keep up with, so to speak.
The majority of users that I have gathered feedback from who use the U2312HM or the similar U2412M find it absolutely fine for all sorts of genre of game. There are some that feel it is not responsive enough for their needs - but for them it is the case that no IPS panel monitor is and perhaps even no 60Hz TN panel monitor is. In short I wouldn't worry about the 'artifacts' as they only pop up during particularly rapid transitions where the alternative is just a blurry mess, anyway. As far as IPS panel monitors go the U2312HM is a good choice if you like gaming. But only you know if it will be responsive enough for you on an individual level.
