This meaning of sharp in connection with clothes always puzzles and strikes me a bit because whenever I hear “sharp” it makes me think of something razor-sharp or pointed, like a razor-sharp blade or a pointed spear. I have always wondered why “sharp” came to be used as a quality of clothes.
It's generally a term of general approbation, yes.
However, a "lawyer in a sharp suit" is rarely regarded as a positive figure. The phrase suggests a slick lawyer who exerts undue influence over a process or works devious schemes for his own or his employer's benefit rather than for the greater good.