In general the K52JC's performance is good. Its Core i5 processor has the power to deal with most tasks with no problems and, unlike the Core i3 processors found in the compared Samsung R580 and Toshiba Satellite A660-14C, it has Intel's Turbo Boost feature. This will apportion more power to a single-core when the other isn't being used, and can have a significant impact when using single-threaded applications.
You can see this advantage in the system performance results, as the Asus scores noticeably higher. This extra performance should prove beneficial in many applications, but if you're just surfing the web or working on documents then both the Samsung and Toshiba have ample performance for all needs.
Moreover, as the gaming testing reveals, neither the faster processor nor the 1GB of video memory has much benefit for gaming. Indeed, the K52JC is actually outperformed by both our compared systems, albeit not by a massive amount. This isn't to say the K52JC is a bad system for gaming, it does an okay job for the money, but it's no better than many cheaper laptops, too.
More worrying, however, is the mediocre battery life on offer. It only just edged over the three hour mark in the productivity test, and fell short of two in the DVD playback test. Evidently Asus, rather than enjoy the increased battery life potential of Optimus, has simply used a lower capacity battery and pocketed the difference - it's rather like opting for an upgrade on Apple's website. As the K52JC isn't that portable it's a somewhat understandable decision, but it does make the presence of Optimus somewhat moot.
Such issues are exacerbated by the fact the K52JC isn't that great value. You can find the Samsung R580 for around £599, £90-odd less, and the Toshiba Satellite A660-14C is available for a similar price but brings with it a Blu-ray drive and some excellent speakers. Asus' two-year warranty adds some value, but taken as a whole the K52JC lacks any specific selling point.
As a debut for Optimus the Asus K52JC is an inauspicious start. A better keyboard would do much to improve this machine, but it lacks any inspiring features and it doesn't offer great value for money. None of this is the fault of Optimus of course, but it's a shame the K52JC doesn't showcase its potential better.