I was in the same boat earlier this year. I shot both, side by side several times before making a decision. What I found is this. The Guardian is an amazing shooting bow. Very quiet and stable. However, the draw cycle leavesa lot to be desired in my opinion. The Allegiance does have a little more vibration, but a lot of that is attributed to the lighter mass weight of the bow compared to the Guardian.

The deciding factor for me was the draw cycle. I shot about 20 shots through the Guardian first, set at 70lbs and when I switched to the Allegiance, I immediately noticed how much smoother and easier the Allegiance felt to draw. The Alley was also 70lbs with the smooth mods in it. To me, the Guardian feels like there is a "hump" to get through at the end of the draw cycle before letoff. Something I didn't care for at all.