Joule LA100 Mk III and First Sound Presence. Owned both and while different, are outstanding linestages. I would happily live with either of them. For detail and transparency, First Sound. For soundstage and that silky smooth (not top be confused with overly warm and lush) presentation, the Joule. There is no such thing as best. And it depends on the amp in which you plan to use.
Best Line Stage
What in your experience is the best line stage tube pre-amplifier you have had an opportunity to listen to in the $2,000 - $3,000 thousand-dollar range (used prices)? If you have the time, please explain what you value most (detail, tonality, sound staging, dynamics etc), as this will give everyone some insight into the performance of your choice for best pre-amp.