They're all pretty smart.

Shang. Though John Smith was a pretty fast learner,i still vote Shang. No offence,but i sometimes think Flynn Rider doesn't even have a brain!!!!!

But street smart.

Also Aladdin and Beast.

Flynn IS smart, although he is definitely not clever. But he managed to get out of trouble for years while being a thief, he tricked Stabbingtons so easily and took the crown, he ran away from the whole army of royal guards more than once and finally he managed to take a right decisions when bleeding on the floor and dying. In terms of being logical or intellegent he definitely doesn't stand a chance against other princes, but when it comes to being smart he is definitely on the top.

He battled the Dragon, knows his way around, got through the thorns and well honestly almost everything he did was fairly intelligent

Aladdin's got street smarts.

Yap

Mulan and Shang, smartest couple ever
well then again it depends on what kind of smart we're talking about. Shang is very battle smart, but Aladdin is very street smart.

easyyyyy

and Aladdin:)

I'd turn this around. Did the princes made stupid mistakes? Shang? He was fooled by Mulan, of course, but more importantly he failed to heed her warnings when it mattered.

Aladdin? He made an endless string of stupid mistakes. Those mistakes drove the story along.

Eugene didn't figure out that Rapunzel was the lost princess, even though it should have been pretty obvious.

John Smith essentially goes AWOL. This counts as a stupid mistake because he knows Ratcliffe is an absolute idiot and that the inexperienced men desperately need him to lead them.

Eric fails to figure out that Ariel is "the one".

Prince Phillip doesn't make any really big mistakes, but he does make one mistake. He doesn't figure out that Briar Rose could be Princess Aurora, even though he knows she has been hidden away somewhere and that Briar Rose has both an exceptionally beautiful appearance and exceptionally beautiful voice. Had he figured it out, he might have been prepared for the possibility of Maleficent's trap.

Neither Prince Charming nor Snow White's prince do a whole lot in their movies, so they don't get points either way.

In contrast, Beast is truly a main character of his movie. He does make a lot of mistakes, but they're not stupid mistakes. They're emotional--first because of his temper and then later because of his love. In contrast, Belle makes stupid mistakes.