Brett vs Killer

Looking to change it up at 3b. Have been running Sheffield out there for forever and wanna try something new. Which do you recommend? Current lineup is:

Beli
Mantle
Walker
Sheffield
Thome
Biggio
Prestige Didi
Posey

I would say Killebrew, as it would keep you with the L/R balanced lineup if you sub in for Sheffield.

Brett has a much easier swing to get used to and allows you to bring it Sheff if its a nasty lefty. He's also a much better defender, tho I know a lot of people dont value 3b def much.

Harmon is a absolute beast. I get him every year. Hits over .350 online with .800+ slug every year for me. Dudes a freak

Brett has a good swing but you can't not get Killebrew with that power. He is the move to me