Although it's not terribly cheap, and to be totally honest, I haven't even used the 12v trigger relay on it - my Belkin PF60 allows for selectable delays, switched/unswitched, 12v in/out - and if you can find them on sale they're often less than $180. Granted, you're talking about more than just the single trigger boxes cost in most cases - but you also get a nice-looking powerstrip out of it as well.
Basically through dip-switch settings and front panel selections you can set any of the 12 rear outlets to be your triggering outlet (or use the IEC cord as a 12V trigger if your AVR doesn't have the standard 1/8" adapter). Then you can further set by bank what the response of the other outlets are.
For example, you could set the outlet that the preamp is on to be the triggering outlet, which then turns on the two amp outlets - followed by all the other outlets. Or pretty much any other configuration.
I don't really give any credence to the "line-filtering" capabilities of the unit - I've never seen anything short of a true, active line conditioner that did anything at all for noise filtering on the mains... but then again I've been pretty lucky with my power here being pretty clean.
I do appreciate the fact that I can use the LCD readout to monitor current loads and voltage drops that might be occurring on that outlet. Basically I just bought it because it was really cheap on sale (no way would I pay the $600 MSRP for it) and it's easier to organize the power cords than it is on a floor strip IMO.
Here's an
old review that will give you some shots of the rear panel and covers some of the features.