Very different decks, voiced for different systems and different eras of music production.
I've own/have owned various spec LP12s including 2007-spec LP12SE, 89-spec deck, 92-spec deck, and Majik LP12 (with Karousel bearing). My personal opinion is that they are all quite different and voiced for 'their time' and the Linn or Naim systems of their day, and the recordings of that period.
For example, the Majik is very good with modern compressed recordings and mates perfectly with modern Linn Majik systems. It will sound much clearer and more tuneful than your existing deck. Whereas, the '92 deck with Linn LK amps sounds great with late-80s / early 90s 'hard' digital recordings. And the Valhalla/Ittok deck combined with vintage Naim amps / Linn speakers is perfect for 70s/early 80s analogue recordings.
So I would think about your system as a whole, especially in terms of voicing and getting a well-balanced end result that is not distracting in any way. I'm not a great believer in upgrading old decks unless you already have a modern system and the upgrade is just one step on the way to a modern-spec deck.
If you have a similar vintage system that you're sticking with then I'd just ensure your existing deck is performing at it's best - i.e. set-up by an experienced dealer and serviced, including the Valhalla which can be done by Class A using Linn-supplied components.
Whereas, if you have a modern setup or are heading that way then I'd dem a new Majik LP12 which is a very nice thing to own with plinth of your choice. It will be a real treat to get a shiny new deck after all these years.