In general the more options you have the better. I run an xlr with amp modeling directly into the helix. I also run the same models through my deluxe reverb and mic it. I have the amp modesl set up so I can turn them on and off, so when I want to record just the amp, I can do that. This allows you to either a:: mic just the amp , b: mic the amp with your processing runnung through it (i use a real sm 57) c: just use the modeling componemt or 4: mix all three together or any combination of same. The SM 57 has a brighter thinner sound and quite often, that 's what you want, you don't want all thoe other frequences mucking up your sound. Other times, the helix models on there own sound fuller and warmer. Mixing the two gets you both, which , depending on the situation, may or may not be what you want. All these things are tools, there is not shortcut to finding what sounds good other then experience and skill and the willingness to try different things. I may not want to hook all this stuff up just to write a song, in which case the helix does great. For final version stuff, I like to do as I mentioned above. That said, for several years I wrote a bunch of stuff for tv and film useage using, in nearly every case, Amplitube 3.