Compare Prince Hal to Hotspur in Shakespeare's Henry IV, Part I.
Prince Hal and Hotspur, two young men from rival families, will face off in battle—and Prince Hal, improbably perhaps to some observers, will win. Yet Shakespeare has carefully prepared us as an audience to see the flaws beneath the surface in Hotspur and the "diamond" in Prince Hal.
Hotspur is a chivalric warrior, noble, brave, honorable, chivalrous, and masculine. But he is also hot-tempered, proud, and intolerant, as well as easily manipulated by his relatives. Hotspur, in his aristocratic self-assuredness and arrogance, has blind spots that make it difficult for him to see the world as it really is. He is one of those people who can't appreciate the value in other people who might be different. For example, early on, in his first speech, he makes fun of courtiers as effeminate, not realizing that even "vile" politicians might have something to teach him. Nevertheless, King Henry admires him for his exemplary external knightly qualities.
On the other hand, the king initially worries about his happy-go-lucky, party-hearty son, Prince Hal, who seems more at home drinking with Falstaff than preparing himself for the monarchy. But Shakespeare's point is that what Hal is doing—hanging out with all sorts of diverse people—is good preparation for kingship. Shakespeare didn't have to put Hal, a royal prince, into the tavern. As eNotes points out, the "tavern" dimension of the play is Shakespeare's own invention and a radical one at that, showing a future monarch carousing with commoners. To Shakespeare, however, a future monarch being in touch with reality was important enough for him to depart from dramatic conventions.
Hal may seem less worthy on the outside compared to Hotspur, but he is developing the "boots on the ground" skills he will need to lead on the battlefield and at home. He may not exhibit Hotspur's relentless chivalry, but like King Arthur in The Sword in the Stone, his way of life is preparing him to be an exemplary ruler, in touch with all sorts of people, capable of discernment, and able to inspire loyalty.
Hal, who is otherwise known as Prince Henry of Wales and the future King of England, is very different from his counterpart, Hotspur. Hal enjoys a good time, and expends his energies plotting pranks with an unsavory element at the pubs. Although he is being groomed to one day be King, Hal avoids his responsibilities in the royal court. He is a work in progress, and the reasons behind his outlandish behavior are much debated by critics.
Hotspur, whose real name is Henry Percy, on the other hand, is an inarguably honorable character who stands in stark contrast to the more lackadaisical Hal. The son of the Earl of Northumberland, Hotspur is valiant in battle and actively seeks recognition for his military prowess. He is charismatic, brave, and loyal, exhibiting a sense of purpose and seriousness that Hal appears to be sorely lacking.
It is a tribute to Hal's perceptiveness that he recognizes the strength of character possessed by his rival. He says of Hotspur,
"I do not think a braver gentleman,
More active-violent or more valiant-young,
More daring or more bold, is now alive
To grace this latter age with noble deeds" (V.i.89-93).
Hal also astutely recognizes Hotspur's tragic flaw - although Hotspur is complex and unfailingly noble, he, unlike Hal, does not have the ability to live in the real world of his times, a world which Hal describes as "the vilest earth" (V.iv.91).
I would add that perception is a huge theme in this play, and must be taken into account when comparing these two characters. We see how the king perceives Hotspur (as noble and valiant and worthy to be a prince) and his own son Hal (as dissolute and uncaring). At the same time, the audience is given a peek at Hal's intent from the beginning, when Hal soliloquizes that he has an unannounced plan to throw off the inappropriate behaviors and appearances when the time is right:
Yet herein will I imitate the sun,
Who doth permit the base contagious clouds
To smother up his beauty from the world,
That, when he please again to be himself,
Being wanted, he may be more wonder'd at,
By breaking through the foul and ugly mists
Of vapours that did seem to strangle him. (I.2)
At the same time, Hotspur is a valiant, honorable man--with a nasty temper and sometimes, the cunning and tact of a three-year-old. He has focused all his energies on being a great warrior but he throws temper tantrums. He also sees no more than appearance in his enemy, Prince Hal, causing him to grossly underestimate the heir apparent on the battlefield, costing him his life. Hal may compliment Hotspur, as symatsuoka says, but that bespeaks his own graciousness and nobility more than Hotspur's worthiness of his praise.