One G and one three-stream N is likely to confuse, at 2.4 GHz given the lack of free spectrum already in most built up areas. For internet access, yes, I'd agree (but G only manages 20megabit on the best kit, I've seen a lot of G kit that can only do 10megabit speeds - such as the old BE Technicolor routers).
The ASUS can achieve a lot more, especially for LAN streaming, and its power output and (due to N and 3 antennas) resilience is much greater than the ancient Netgear DG834 and similar derivatives.
Personally I'd put a Netgear box that old into some sort of bridge mode, or even enable DMZ and put the ASUS into it at worst case. The technical differences between those routers are dramatic - unsurprising when you look at the age
James BT Infinity 2
19/09/2012 - Speeds 49 / 8.2 Mbps - Sync 53 / 9.5 Mbps @ 470m
Huawei modem -> RT-N66U -> Switch -> PC/Mac/Linux/NAS/Phone/TV - last speedtest
13 years of broadband - 1999 ntl:(512k/1M)/BTbusiness(2M)/Metronet(2M)/Bulldog(8M/16M)/BE(19M/16M)/BT FTTC(46M)