Well ... I've actually only ever been to one muffler shop, and for good reason. Service here is absolutely excellent: patient, fair, attentive, friendly, and diligent. I couldn't ask for anything better. As difficult as it is to find an auto repair-related shop that's honest, that you can trust, and that does good work, Henry's on E. Millbrook all of that and more.
I started going there years previous (~2007?) when I stayed in the condos across the street. Thank goodness I found them. I've saved so much money by going there. Though it can sometimes take a few tries to find my exhaust leaks on this old ('88) vehicle, we eventually always get it squared away -- expertly and at an affordable price. They just don't charge you for anything they don't have to, unlike other shops that take on extraneous fees just because many clients don't know any better.
Julie (at the front desk) is a sweetheart and is always a joy to talk with, and Donnie (the primary auto tech I've only ever spoken with) is SUPER knowledgeable, fair and honest, and is always, always willing to (thoroughly!) answer whatever questions you have and make sure you understand the work you're getting. He will ALWAYS come let you know what needs to be done *before* doing any work and will explain what's going on IN DETAIL, offering to take you out to see for yourself without you even having to ask. Not only that, he presents you with all possible repair options (even if some are honestly bad ideas -- he'll *tell you that*), and he allows *you* to then make an educated decision based on his recommendations and the facts.
I tell people all the time that I wish Henry's did more work than exhaust systems, but that's not going to change any time soon, unfortunately. ;) I've gone to the one on Capital and didn't like it, so I always still go to the one on Millbrook. Though it's further away, it's totally worth it -- highly recommended! Just make sure you make an appointment because, though it wasn't the case years ago, these days walk-ins are scarcely possible.