Jesse,
I shoot the same weight and drawlength that you mentioned and I have the legacy. I don' t think the legacy is a very fast bow. My arrows weigh about 436 with a broadhead on them. I switched to a different arrow that weighed 98 grains less and was shooting 273 f/s. I shoot a string loop and have dampeners on my string as well. I know that I picked up speed with the lighter arrows but my old setup is rock solid out to 50 yards. Its not as flat with my heavy arrows but if I use my rangefinder the animal is hit just as precisely.
I don' t know anything about the bowtech bow. I' m guessing it would be faster. I' d shoot both bows and see which one feels the best. There' s a lot more to consider here than speed.
will