Welcome to Pals
Reading the reviews on the link you provided, including the ones that mention using it for gaming, it seems like a great monitor.
Unlike CRTs, LCD and Plasma displays are optimised at their native resolution so running them at lower or higher resolutions would cause some drop off in image quality.
By how much and if it is a problem though would be subjective and up to the person using it.
I dont know if the consumer rules are the same where you are but here in the UK, if you buy online and find out that it isnt to your liking, then you can return it within 14 days for a full refund. It doesnt even have to have an fault, you can just have changed your mind.
If you have a similar law then I would suggest buying it online and trying it out. If it doesnt look as good as you expect when playing your games then send it back, even if you have to pay the return postage, its better than having spent a lot of cash and being stuck with it like you could be if you bought in a local store.
Hope this helps