#1 I would have to say for most (not all) effects you should not use presets. Especially with a compressor or eq preset. You can easily take away the energy and movement of a sound with too much compression or eqing in/out frequencies that kept the sound solid. Some effects are fine with presets but be very careful with getting comfortable using them. There may be a sound(s) that do not work well with that preset. The more you experiment and research each signal processor the more comfortable you will feel sculpting your sounds with effects.