Interestingly I found the N16 stock firmware to have the best QoS of any router I've used. It requires no configuration and always seemed to work great. DD-WRT's QoS, on the other hand, can require significant effort to configure correctly.
Every router I ever owned that I put Tomato firmware on I could never get any version of QoS to work correctly.
It's a free firmware and great other than QoS but who am I to complain :/
Hmm, I've used QoS in Tomato for years. The early versions of Tomato had a very simple QoS build. The latest Toastman builds have some 30+ rules. All versions seem to work OK for me. But I'm sure it depends on traffic and would be hard to debug if it did fail.
I feel like it'd be cheaper for manufacturers to write better QoS drivers specifically for tomato, or wrt, than whole new firmwares, surely?