If you like a nice aggressive sound go with the muffler delete. I had a local shop make and install a muffler delete Y pipe for $160.00. The sound is incredible and not as obnoxious as some say and think.
That being said all the mufflers listed above sound great to. I had the FM 50 American thunder and was not crazy about it. Had a nice rumble but I like loud.
Up to you really on how you like sound. Here's a clip of my muffler delete at cold start up and a small rev.
IMO Mufflex is the best bang for the buck.. They use magnaflow mufflers, or you can get the delete and it's very hight quality stuff.. If you want name brand, then you will pay for it.. If you want cheap and good then get a mufflex setup.