I ignore the effects loop myself, but -- that's based on practicality, not on tone. Normally, I'll switch an effect on and off at different points in a song, so I have to have the box at my feet. If I used the loop, I'd be adding a LOT of extra cable: from the guitar to the amp; then back to me; and back to the amp again.
That being said, I rarely use FX with the Classic 30. I mostly use that amp at home, and for recording. What I'm trying to get out of it in that context is the tone of the amp, combined with a particular guitar.
That being said, in your situation, with 10-12 FX -- I'd be thinking hard about strategy. In your case, you might be better off with the delay and/or phaser and/or chorus and/or flanger running in your effects loop. You might also want to think about switching and routing solutions that run right on your pedalboard (I have a Boss LS-2 line selector, for when the routing starts to get hairy).
As for complaints -- well, I'd probably use this amp more, if it had a brighter overall tone. And it's not loud enough to compete with my drummer!
"It looked like a giant green gum drop to me."