Ive not DJ'ed for a few years now so i might be missing the point, but for me the important aspects of a mixer are: good solid feeling faders and xfader, with no crackles, good EQ's with a center notch so they can be returned to exactly zero easily as this is how the tune is suposed to be played, and reliability this depends on how much use/abuse it's going to be getiing, ie install or is it going to be dragged around pub/clubs/fields tents/ warehouses ect.

DJ effects in my opion should be limited to loop sampling with maybe some good quality filters. Hearing some DJ putting a flanger across the mix just sounds naff to me.

Im unsure of the usefulness of multiband effects on the mixer aswell, I can see this totally destroying the spectral balance. If the person using it truly understands what they are doing with this then I feel there time would be better spent playing there own productions.