I've run both (and I sell both MM and Steeda parts). I have to vote 5 link. It's more adjustable, and has less unsprung weight no TA hanging off the axle. You can monkey with your instant center, your anti-squat, it's lighter and less prone to brake hop.
I'm very familiar with TA's, I have an F-body too, and they are TA cars aside from having run TA equipped Mustangs.
Now I have no loyalty to either Maximum or Steeda (and not Griggs either). I sell the first two when the parts either have suit the need... Much like what folks like for food, or women, or cars, tastes will vary. The above reasons are my reasons.
7x SCCA National Champion + 7x SCCA ProSolo Class Champion, 2009 SCCA ProSolo Overall Champion
I drive them, I compete in them, I sell more variety of brands than any other company.