I went with the Mufflex DOD24M which is based on the MagnaFlo 24". The thing I like about it the most is that it is no louder then the OEM muffler but it is about an octave lower in frequency so you definitely hear it. There is the perception of louder, but when tested with a sound pressure meter it actually measured slightly quieter then the OEM.
My neighbors across the lane in their late 80's have commented that since I changed my muffler they can hear my truck when I start it in the morning and can now hear me when I drive down the lane to my parking spot. They also commented on how good it sounds
and were amazed that it could sound like that but never get annoyingly loud.
I love my neighbors.....and my 24" MagnaFlo.