I really like my Diamondback, which is last years model; very solid hunting bow. They have pretty simmilar specs but the Pirana has about 2 inches more of brace hgt. with only like 5 or 6 fps speed loss. Should be much less critical than my DB which is great. The riser (which has much less reflex probably almost nuetral)looks to be the main diff between them, and ax to ax is the same. The most impressive thing to me was how quiet the DB is. Makes a great hunting bow IMO and is very accurate within my hunting range. I went 2 for 2 with it last season on deer plus arrowed the same squirrel twice from 20 ft up at 12 yds. Not real well suited for backyard practice out to 50 or more though.
I hope this helps but I wish you could find somewhere to go and try one out before you decide on it. I think Pearson is underrated and you could buy 2 for the price of other high end stuff.
Later-
Chief