He only plays a few games with his friends: FIFA, COD, Formula 1. That's all. All games play fine with no lag as far as I am aware, otherwise I would have been on the phone to Plusnet. But this might be due to my good connection, I don't know. I use wired connection to PS.
I am afraid I cannot recommend any router as I am not an expert on them. I did my research when I joined Plusnet and Netgear was one of the router people mentioned at the time, so I got it based on my previous possitive experience with Netgear DG834. Looking at the reviews now on Amazon, it does have quite a few negative ones, but it works fine for me and there was a new software update for it last month.
I don't remeber tweaking the router but did follow some online guides on how to optimise the Playstation for gaming instead.
I think ASUS routers are now very popular and capable, so you might want to ask the question in the
DSL Hardware forum.
And finally, I had some initial teething issues with Plusnet and feel it's worth mentioning.