Your question doesn't provide enough information to give you a really well thought out response but here's my take anyway. I've owned my current LP-12 since '84 and have done most of the upgrades offered along the way myself. In spite of it's detractors it is a really good deck and once tweaked stays that way unlesss you move it around incorrectly a lot. The only failure I've had was the Valahlla which I repaired myself for something like $10. A lot of the performance is dependent upon the tonearm used with it and proper setup. They are very inexpensive on the used market for their preformance. I love mine and wouldn't sell it even if I were buying a better table.
I know several people that owned the Ariston tables. Their comments when they come over for a music get together is that they wouldn't have jumped into digital if their old tables sounded as good as my Linn. They look similar and may be just great. I don't know. I've also owned Thorens tables dating back to '71 and my favorite was the 125. IMO, they are no match for the Linn but can understand an argument that they are equals. Again, as I stated above your happiness will be determined by the arm, etc.
I don't put a lot of stock in the compliments I receive from friends who drop kicked analog 25-30 years ago. There are just too many variables in the mix to toss what they owned under the bus. I'd guess I could work on one of your tables with a newer arm, properly mounted "okay" cartridge and they would be surprised with these tables as well.
I have no compelling reason to upgrade my table. I'd probably feel differently after new amps and speakers were inserted.
The used sweet spot is a braced plinth, Valhalla, Cirkus bearing and Ittok LVII Linn. If you can peddle yours and buy the Linn without much more outlay (+/- $400) then I'd suggest going for it.
