I think everyone should be plugging their Axe FX directly into a sound system and taking full advantage of the cabinet simulation, and the isolation / elimination of mic bleed from other sound sources in a live environment. That said, if you are not playing with a sound system, and you need to project your tone from your backline, you could slave your 5150 power amp and turn off the Axe FX power sim and cabinet sim in the Global settings, and then easily re-engage it system wide for home recording or for headphone jamming quietly. There are plenty of threads about splitting the output so left has cabinet sim and right does not, so you can send your left output to the mixer, and use the right output to feed an amp onstage to use as your monitor. There are so many options. Unfortunately, some of those options are very costly. That is why my preference is to use the Axe cabinets and send an XLR to the sound system. Then I can use in-ear monitors, or I can drive a Marshall AVT275 slaved as a power amp through the stereo FX return on the back of the amp. It's not perfect, but it let's me feel like I'm moving air, and I feel the cabinet vibrating. Of course, that means I'm sending an Axe FX signal with amp and cabinet simulation into a Marshall sealed 2x12 combo, but again, it just gives me a security blanket and stage volume. The real tone from my rig is a direct XLR stereo feed to the sound system. Marshall AVT's are not expensive, and that little amp, although solid state, sounds very convincing as a stand alone amp, I must say.