E30 is a better-looking car, imho. E36 is quite possibly a better car (interior trim excepted.)
M44 in an E30 is a fabulous performance change.
M43 in an E30 provides better performance than most E30 4-cylinder engines, is reliable, and economical. (But no-one does this!)
I do feel an E30 with a 4-cylinder engine is sportier, and with a 6-cylinder engine is more suited as a lovely cruiser. Just a weight distribution thing.
And I know many people will disagree.