I picked up an RT-N16 about two months ago specifically to put Tomato USB on.
When I first got the router, I tried putting TomatoUSB onto it but as I kept having connection issues I decided to leave that for the time being and try out the stock firmware first.
I tested that for a few weeks, didn't experence any major issues but it didn't seem all too stable so I decided to give custom firmware another try. I read all the instructions super carefully this time, but still ended up with the same issues - wireless speeds are horribly slow, unusably slow.
I did some further research, some others with the RT-N16 suggest things like switching from TKIP/AES to just AES, going from auto channel selection to a specific channel (or vice-versa), or using 20MHz instead of 40MHz. I tried all these solutions, and had a small amount of success in that my router can now sometimes report a wireless rate of 150Mbps - it failed to ever go over 65Mbps using the stock settings on TomatoUSB.
But the thing is, I can't leave it on these specific settings and be happy, because it's still fluctuating and going down as low as 5.5Mbps. In fact, it's more often closer to the bottom than it is to the top.
So what do I do? Why is the RT-N16 even listed as officially supported by TomatoUSB? It doesn't seem like I'm the only person with inexplicably slow wireless speeds on this router. I haven't forgotten about static and noise and whatnot, but these fluctuations seem more drastic than that - plus it seem to get better with random settings changes before getting super wonky in a few minutes.
Despite what everyone says I found the stock Asus firmware much better. Sure it would drop my connection one in a while under heavy load, but at least it was always at 150Mbps.