The Onyx does have nice preamps. I have a 1640 that I use in my studio. Yes the send is before the eq's and the Mackies have very nice Perkins eq's. You can buy a modded Mackie, which is a little more or if you are handy with a solder iron, you can do it yourself. The sends will then be pre-fader or post fader what ever you like. There is a write up over on mackies forum site about modding the units. Here is the mod link
Mackie Forums Home: 1620 Modification Instructions
Or here is the link to the purchased modded units. you choose pre-fader or post when ordering $200 more.
Mackie ONYX 1220 Premium 12-Channel Analog Mixer