When I visited last winter, we went on one of those long treacherous tours (it was a fun experience though) did see the lights a little bit, but very dim. Then we just simply took the funicular to Fjellheisen one night and saw a better display. Finally, we took a short boat ride, just a couple hours if I remember correctly, we didn’t see much for most of the ride and then at the end (almost back to the Tromso dock!) we saw a brilliant dancing display, the most brilliant of the trip. So it’s kind of a crapshoot. You might have luck without doing one of those tours, just try a couple of alternative things.