It depends on the position. But if your asking on the puzzle given, I think they're all interesting but the queen is the strongest. :D

Nice puzzle indeed!

The queen requires the longest line to win. Cannot possibly be strongest! :)

those puzzles were very good.  In the puzzles, the knight was best.  And in my mind, it is my favorite piece.

Very nice puzzles! Thank you for sharing them. The second one is the one I liked the most.

So you based the strongness of the pieces on the lines given?

nice!!!!!!!!!!!!!!!!!!