Have used 3 Asus systems in the past 6 months, none of them were dumped as bad machines, merely changing requirements;
Asus UL80vt; Extremely good battery life, quite good performance, initially had a problem with the hybrid graphics setup between the integrated intel and discrete nvidia but stock 10.04 worked fine on this, the only catch was the ath9k chipset for wifi, which although it did work would randomly drop out and require a reboot for reconnection, switching to the preempt kernel line fixes this issue.
Asus N71JQ; Good middle of the road system bang for buck wise, ATI drivers were significantly shakier than Nvidia, but not enough to dissuade me from ATI entirely in future purchases, exact same problem with the ath9k chipset as with the ul80vt.
Asus G73Jh; Ridiculously awesome performance and the hybrid drives on the system make this perform significantly better than even desktop 7200rpm drives (at least for read), the cost is significantly lower than even a mid range MBP and you simply cannot get these specs on an MBP at any price. The drawback is that the video card is past the bleeding edge that is gracefully handled by the stock fglrx drivers from ATI.
I spent days first fixing this in ubuntu 10.04 by manually patching kernel driver files and rebuilding the fglrx modules myself, followed by this being broken a month later when upstream went ahead and fixed the same problem in a different way, resulting in extensive maintenance to push out the conflicting fglrx mods. That said, this issue should actually be fixed as of the present 10.04 release and the double dose of pain I got may have been an artefact of my specific case. If this is really the case this is an awesome development rig. The only other drawback is that old ath9k chestnut, same fix as required for the other two mentioned model, the preempt line of kernels fixes this.
The only other issue affecting all three systems is that the touchpad freeze function does not work without extensive kernel level messing around and I couldn't be bothered to go that far to fix what I felt to be a minor issue (it was most pronounced on the ul80vt due to the size relative to my enormous hands and least on the G73jh for the same reason).