I'm sure you'll hear this often, but mufflers are very personal. It depends on what you want. I chose the Flowmaster 50 because I wanted a deeper sound without waking the neighbors or announcing myself down the road. For the record - it actually MAY wake the neighbor on my driveway side, but it's not considered "obnoxiously loud"
(I live in a somewhat dense development where houses are only about 60 or 70 feet apart). My startup in the early am does have a noticeable difference in sound compared with an average car but that's what I want.
I spent hours on youtube listening to various models and finally chose the Flowmaster 50. It gives me some cabin hum at lower rpm's but that's to be expected when you want a deeper exhaust note. I only did a one-to-one swap of my stock to the 50. I'm happy with it but again it depends on what you're looking for.