I love the WRT54GL as much as anybody, but it just can’t keep up anymore. Not just the WiFi, but the overall throughput.
It’s puny MIPS can’t push VPN beyond 10 mbit because it has to compute all that crypto with that itty bitty CPU. Even straight up DD-WRT with no crypto pegs my iptables at about 20 mbit sustained. Stock might be a wee bit faster, but you are still pushing an old warhorse beyond anything it was orginally designed to handle.
The TP-LINK puts the crypto onto the Atheros SoC, and with dual G antennas it can push 54+54=108 mbit/s without breaking a sweat.
TP-LINK for the ip-QOS. I wouldn’t own anything else.
DD-WRT on a WRT54GL at one time was the way to go, but it’s day has long come and gone.