Ask yourself what you are willing to sacrifice or compromise on?
Speed a requirement? then you might be looking at a little harsher drawing/shooting bow (I said might for any nit-pickers out there

)
A shorter bow could be a little less stable than a longer axle-axle bow
And so forth.
Decide on what you want and then judge the bow accordingly.
If you do not have any preconceived notions on what you want, then buy the bow that feels the best to you.
My bow shopping this winter/spring included a variety of bows, the one I ended up with wasn't the fastest/shortest/heaviest/longest/slowest/etc.....but it was the one that met the most of my criteria.