The petrucci has a floating bridge which I dont like, plus I like to alternate tune a bit like a quick drop D here and there and then back to standard on stage, so the Silo was the guitar for me, I swapped out the pups and it sounds great, also the petrucci has a wider and thinner neck, so you really need to go play them both and see, different feels altogehter but I went with the silo to compliment my axis SS -