Funny enough, I kinda like the C12. The current AA battery version is pretty ordinary though.
When I run our Plarail Christmas layout, I like to use the older C battery version in rotation with the usual C62 and D51. Come to think of it, the “big” C12 is a bit homely too! It’s oddly proportioned compared to the bigger steam locomotives. But I like running it!
I wouldn’t say there’s one of these little trains that I dislike. Maybe it would be fair to say that locomotives like the B20 or “big” C12 are endearingly odd rather than ugly? Inelegant perhaps?
In real rail fanning, sometimes, the more weird, misbegotten and downright ugly a locomotive is, the more people seem to love it. They stand out from the crowd of massive fleet purchases and catch attention, for good or ill. Here in the US, the old rebuilds like the Katy Alco/EMD hybrids and the Santa Fe rebuilt CF7s are great examples of “so ugly that we love them” locomotives for some railfans.