Hi Castamasta,
I haven't had any personal experience with the Penns but I have Shimano Baitrunners, with 3 being the 6500B series. I have one new 12000 'D' series baitrunner but I am not entirely happy with it compaired to the 'B' series. A couple of mates have had major failures with the new 'D' series already while the 'B' series just keeps on going strong. Hope this helps.
Cheers
Carry