I have/had both. I replaced the Linn with a Michell Orbe and never looked back. I think the LP12 is overly fussy and a PITA to ste up (spring bounce). I have a VPI
HW19Mk3/mod'd Rb300 in a second system. I mainly use it to play my older 60's-80's purchased LP's. It may not be the most resolving TT but it is musical and sounds great with new and old LP's. I was really taken by suprise how good it sounds. My friend uses a MkIV and it sounds great as well. The nice thing about it is that you can upgrade it gradually with PSU's, SAMA, acrylic or the older heavier platter.
I'm curious that you are choosing btwn two TT's at opposite ends of the spectrum. I think there are so many TT's out there as good or better than a LP12. If you do a lot of listening to used LP's and rock I'd go with the VPI. I never heard a LP12 (my own or any dealers) do justice to older rock Lp's. My Michell totally trounced my Linn in that dept.
Any chance to go with a Basis? There is a used 2500 w/o arm for sale. I've heard that TT w a Graham 2.2 and really liked it. It's an awesome deck.