TP,KGLL.
Millsap was overlooked coming out of college and I agree that many people have been dismissive of him here as a FA for us, mainly because of his age.
The guy is a tough, position rebounder, not overly reliant on athleticism, but rather strength and guile. He reminds me of a bigger, stronger Paul Silas. Millsap's game will age well.
I would rather bank on Millsap not breaking down than Blake Griffin. (Of course, if you could guarantee that Griffin won't break down, I'd take him, but that's a potential franchise-crippling gamble.)
I, as others on this thread, have suggested over the past month or two that he should strongly be considered by us in FA.
He and Horford and IT keep us contending-relevant for the next 3-4 years, and we get to add BK '17 and '18 to Brown and Smart to contend into the future.
Hayward's my first FA choice, but Millsap is 2nd.