The little Honda is a sweetie which I took cruising for years when we were sailing, and now tote along on lots of camping trips. The Generac doesn't put out pure sine wave power but ran my house without a blip for a week last winter. I'm pretty happy with it. The massive and extremely heavy Black Max puts out really dirty power that makes my furnace gas valve buzz like a mad hornet. When this generator is running it sounds like a 55 gallon drum full of old car parts rolling down a hill. All three cost less than $1000 new when they were bought. So you get what you pay for. 

Plus, jacking with mufflers often screws up engine performance.  From what I understand, a certain amount of back pressure is generally designed in.  Over-muffled & there's too much.  The other extreme - straight pipes - and there isn't enough.  Either way, performance takes a dive.

edit PS: With the 'contractor' type of generators, you likely won't get Pure Sine Wave if that's important to you.  The closest contractor type of genny I've come across that's still an inverter generator is the Yamaha 2800 at around $1600.  And it's still pretty noisy from what I'm told (as compared to the Honda and other Yamaha inverter gennies).