I have. The ones I tried weren't my favorite, so I thought I'd try Linn's own High-output attempt. I haven't done much listening, but the Adikt cart really does boogie. I like it with rock 'n' roll. I think my Arkiv is better in soundstaging and detail, but the Adikt has a nice pace and excitement to the music.
I have two Linn LP12s at the moment, and I think I'll keep both. The LP12 with the Arkiv runs through my Counterpoint SA5000's phono stage, and the LP12 with the Adikt is running through the Cornet2 and into either my SA5000's line stage or the Clarinet linestage.
Both setups sound wonderful but they do have their own strengths and weaknesses...