I'm not one to bash any product (I'll recommend one over another, but rarely take the stance of turning someone away from one)... Having said that, I think I'd be pretty hesitant to shoot Sonics at anything other than small game. I received several from Liberty when they were giving them away last year, and the tolerances on them was often poor, and I've seen and read too many stories of them not holding up well to flesh and bone.
There's too many good fixed-blade heads out there to chance it with those. I used Slick Tricks for the early part of last year, and they're a good head. I finished up the year using Muzzy MX-4's, and I'm really excited about the new MX-3 this year... In fact, I just shot my first two broadheads of the year earlier tonight and shaved the fletching off my MX-4 tipped arrow with an arrow outfitted with my new MX-3s.
Something's screwy going on with my image-hosting site; obviously the grass to the left should be at the bottom of the pic, making these first two shots of the year a bit high... Still, I'm happy with the way they grouped. In fact, not only did I shave two of the flecthings off the first arrow, I dinged up one of the blades on my MX-3 as it slammed into the MX-4 already buried into my Morrell Yellowjacket.