the only thing better than a fritz trainer...

is a live master(im.gm)giving lessons on skype or in person.  Fritz trainers are a very cost effective way to get expert training they are a dvd-rom with video linked to the chessbase program for instant analysis and playback.  all your favourites in chessbase are available for expert analysis.

I like Fritz trainer, don't get me wrong. I have  two of them, have gotten excellent use from them, and would buy them again.

That said, I don't think is the best or the most cost effective training I have gotten. To name two, I think the Yusupov book series is outstanding if you are willing to put in the work. And I bought Dvoretsky's Endgame Manual on Chessable and that has been great value as well.

american fritz trainers may not be as good as european for political reasons

what i mean is i assume usa fritz trainers are very trappy and thus not to the general more patient level of play of a european trainer

i use the fritz trainer in a specific way: first i go through the trainer to familiarise myself with the lines, then i go through making notes on the lines in a notebook then i research the lines in chess books using the notebook, books and computer program chessbase.