I tore 'em up for years. Finally switched to transom mount only for all units.
Never broke another one.
The units on a trolling motor take a major beating. They're going to break.
Something to consider.
Consider that you are looking at what's behind your boat and some people are interested in what's at their feet. IMO a transom mounted transducer is only useful for graphing with the big motor. Transducer for the bow graph belongs at the bow.
Could be important, length wise, if you're vertical jigging or don't have gps, otherwise you can follow contours, fish and catch plenty of fish, with a transom mount.
....and no broken transducers.
Of course there's always TMs with built in transducers too.