Comment Tried a couple recently, settled on Asus RT-N56U (Score 1) 334
My WRT54GL wasn't keeping up either with DD-WRT. Tried Tomato, but it just didn't do the trick for me. I tried the Linksys E3000 model, but my throughput went down by 100K/s. I swapped that out for the Asus RT-N56U and my throughput has never been better! Stock firmware is sufficient, and it has most of the features I wanted. Only missing feature was dns-o-matic support. QoS support is detailed enough for my needs (DNS, then VPN, then gaming, then everything else).
I know that custom firmwares typically let you do more, but I'm quite happy with the stock firmware on this model, for now at least. Still have to try the UPnP feature though.