It may work MUCH better in the loop of another amp though. Because rules are made to be broken, and some may like the sound of the chorused signal preamped, vs. the preamp signal chorused. Do what your own ear says. Don't be a ninny. No effects sound that great in the loop.
Most pros just have the sound guy take care of effects with the mix.
Really the best way for the average person is to by an amp with the effects built in or have the sound guy do it after the power amp. You'll have to get a load box to take it down to line level, and then run that into the effects. Or have the sound guy add the effects on the mixing board. I have two Marshall's, A 6100LM Anniversary head and a Slash Signature 2555SL head. I tried it in line befor the amp.