In recent years, the good prince has been Prince William, the responsible, handsome, self-effacing heir to the throne. The bad prince has been carrot-topped, pot-smoking Prince Harry, partying too hard and wearing Nazi gear on a boozy night out.
Then Harry went to war and William started flying around England in his Royal Air Force helicopter as if it were his own personal toy, bending military rules by dropping in at his girlfriend's house.
William, 25, is seen as pampered and overindulged, and Harry, 23, as a gallant soldier who put his life on the line for queen (in this case, grandma) and country. At least that is the prevailing public view as embarrassed military officials admit they goofed by letting William take the pricey Chinook out on joy rides.
"It shows William in a bad light," said celebrity publicist Max Clifford. "It's the whole spoiled brat syndrome. If any other young officer in the RAF were to do this, they would probably be kicked out of the forces in two minutes."
"It basically says all the wrong things. It says because of who I am I can do what I want. That's the sort of message that upsets the British public."
Harry's dogged insistence that he be allowed to go into battle with his mates rather than get a cushy post back home has impressed the British public. The fact he looked terrific in uniform did not go unnoticed, either - at least by female readers of British newspapers, which published hundreds of photos of the soldier-prince.
And William was not helped by the shortage of Chinook helicopters hindering the British war effort in Iraq and Afghanistan. Some acid-tongued commentators pointed out that the Chinooks should be used to support British troops, not to indulge William's "top gun" fantasies.
The role reversal comes after several years in which Harry has received occasionally harsh criticism while William had been put on something of a pedestal.
To a degree, this has even applied to the young women in their lives. The press has given William's paramour, the elegant, dark-haired Kate Middleton, rave reviews as a possible future queen, but has been less kind toward Chelsy Davy, the blonde Zimbabwean who is Harry's frequent companion.
There's a great wellspring of public affection for both young princes, who suffered the sudden, traumatic loss of their mother, Princess Diana, when they were just boys. But royal watchers fear William may be squandering this good will.
"I just think in a modern monarchy you cannot do this sort of thing and expect to get away with it," said author Robert Jobson, who has written about the royals. "You have to be accountable. I think William has made a mistake and he should realize it."
William's questionable sorties took place when he was attached to a Chinook squadron as part of his Royal Air Force training. He completed his basic training several weeks ago and received his wings in a ceremony attended by his father, Prince Charles, and his girlfriend.
The press has been poking fun at William since the flights were revealed, with some columnists pointing out that no British girl will be satisfied with a boyfriend who brings a bouquet of roses bought at a local gas station as a gift, when the future king can woo his beloved by landing a Chinook in her garden.
But some military men defended the prince and the instructors who okayed his flight plans.
Charles Heyman, a former officer who edits "The Armed Forces of the United Kingdom," said helicopter pilots have always bent the rules. He said he used to fly with a U.S. airman who used his military helicopter to scour the countryside for vintage cars he could buy for bargain prices. When he saw something he liked, he would swoop down, land, and make an offer.
"It's the sort of things helicopter pilots have done forever," Heyman said. "They've landed in their girlfriends' gardens all over the UK and all over the USA. It is illegal by service standards but they can always get away with it. Some people could say it's part of legitimate flight training, but really it's not. You'd have to really stretch to say that."
Still, he said the fact the both young princes are active in the military is important.
"It raises the status of the military and it shows the top people in society are part of it, and that's good for morale," he said.