Batman and Joker share the most complicated relationship in DC. Batman is the thesis of Joker's antithesis. The clown prince of crime was born due to Batman's negligence. Proof enough: The Killing Joke (1988), and The Man Behind The Red Hood, Batman Vol. 1 #168 (1951).
Batman and the Joker don't only share a hatred; there is a co-dependent relationship dynamic between the two. The two have a unique camaraderie, an opposing love if you will. Batman's benevolence counterbalances Joker's malevolence.
Both Batman and Joker are unique in their aspects. There are things the Caped Crusader can do, but the Joker can't. And there are countless things that the Joker can do, but Batman can't. Here's the list.
10 JOKER: NEVER FAILS HIS SIDEKICK
The Joker's most effective side-kick, Harley Quinn, is pretty much alive in every story arc. Never has the Clown Prince of Crime, lost this one. The Joker may shoot his cohorts here, and there, Harley remains a constant.
Despite his grandeur, Batman has failed his side-kicks, the many Robins. Take Barbara Gordon, for example, in The Killing Joke; Batman was unable to protect her against Joker's invasion. Batman took Robins under his wing; although he could never keep them safe. Not only did Batman lose Jason Todd to Joker, but he also lost his son Damian Wayne to the Heretic.
9 BATMAN: CAN AFFORD THE BILLIONAIRE PLAYBOY LIFE
The Joker is neither a billionaire and nor a playboy. While Bruce Wayne can sway women with his charm and persona, the Joker can only scare them. He's only gotten so far as to manipulate Harley Quinn to jailbreak out of Arkham. As goes his financial position, he wasn't exactly born with a silver spoon in his mouth.
Bruce Wayne, on the other hand, inherited his father's Wayne empire. He is the CEO of Wayne Enterprises. Critics have gone to the extent of calling his billionaire/playboy lifestyle unrealistic, but it is what it is. Remember the time when Bruce said money is his superpower?
8 JOKER: CAN MAINTAIN A SECRET IDENTITY
In the canonical storyline, Joker's identity is debatable. The best readers could get was the Red-Hood arc. Joker has many origins. What's common throughout is that no one actually knows where Joker came from. It's not at all firmly established. In Lovers And Madmen, Batman Confidential 7-12 features him as Jack - a bank robber. In Batman: Zero Year Vol. 2 21-33, readers are made to believe that the Joker could be Liam Distal, the leader of Red Hood gang.
Bruce Wayne, on the other hand, isn't an object of mystery. His identity is pretty deducible. From his Tim Drake to Jim Gordon and Hugo Strange, everyone has been able to deduce his identity. In Justice League Wayne upfront told Aquaman about his real identity.
7 BATMAN: HAS A SUPERCOOL HIDEOUT
Part of being a billionaire is owning some of the coolest bachelor pads. Bruce may be terrible at hiding his identity, but his Batcave is impenetrable. Known as one of the coolest hideouts of all time, what's cooler is the way Batman enters it. He turns the handles on his grandfather clock to 10:47, the exact time his parents died. And voila! It serves as a gentle reminder of why he chose the vigilante life in the first place.
The Joker cannot afford a bachelor pad as swanky as this. He does have a temporary base from time to time. Besides, it only helps his character if he is shown to be a homeless lunatic.
6 JOKER: YIELDS A GUN
This is more of a moral conundrum than an ability. If fans had a nickel for every time the Joker yielded a gun at his henchmen and enemies (Harley included) they'd all be rich. A rough estimate tells that the Joker has killed over 800 people. He plans to take the figure onwards and upwards.
Batmanrarely goes for the kill. He has yielded a gun in his early years, but that was that. The focus of his character shifted towards capturing, torturing and eventually taking criminals to Arkham Asylum. In the most watered-down version, it is said that Batman doesn't use guns because his parents were killed by a gun.
5 BATMAN: HAS THE ABILITY TO FLY
They don't call Batman the caped crusader for nothing. Sure, he can't fly in the traditional sense of the word. But he has the body maneuverability and sleight of hand to move his cape. He's seen maneuvering his way from dingy buildings to the nooked corners of locales with ease. His grapnel gun and Bathelicopter also come in handy to glide and fly.
The Joker neither possesses maneuverability nor gadgets to fly/glide him around. He may be swift and agile at best, but he lacks to ability to fly.
4 JOKER: CAN AFFORD TO BE POOR
This simply means that the Joker can afford to be a supervillain without money, but Batman can't be a superhero without money. The night Joker was born, he was either a criminal, a thug stealing for his pregnant wife and he had lost everything he had. Throughout Joker's career, he's managed to wreak havoc with little at his disposal.
It wouldn't be crazy to call Batman a sum of his riches. He inherited his father's empire, billions of dollars to say the least. While money doesn't buy peace, it buys him the super cool gadgets to help maintain peace.
3 BATMAN: IS PICKY WITH SIDE-KICKS
Employing murder theatrics on a larger scale means that the Joker needs as many men in the game as he can. The larger his team of gag-clowns, the more impenetrable he becomes. From the very beginning, starting with Gagsworth A, the Joker has recruited lunatics of the highest order. In order to further his cause, the Joker has turned wise ones into Lunatics (Read: Harley Quinn) who in turn have inspired his wave of terror and mayhem.
But not the caped crusader, he's picky when it comes to choosing his Bat-family, let alone hiring lunatics. Helena Bertellini, for example, was fired from her job as side-kick because she disobeyed clear cut directions and orders. Stephanie Brown met a similar fate for wreaking havoc.
2 JOKER: HE INSPIRES FEAR
None of the average villains hold a candle to Joker. He's unmatchable in every sense of the word. The Joker is a murder clown with a scarred face, red lips, blood-shot eyes and green hair who delivers the best punchlines. It is not the physical violence that shakes a soul but the psychological aspect of it. Imagine an average villain stabbing people, now imagine a scary clown stabbing people but laughing aloud all the while. Fearsome, isn't it?
Batman may torture people but he doesn't inspire fear to the same degree that Joker does. Batman is a vigilante who has taken an oath to protect commoners. He may lose his inhibitions, but those are moments of sheer anguish and frustration. Other than that, Batman's persona has a wholesome vibe.
1 BATMAN: HE EMBRACES HIS PAIN
Batman from the very beginning of his story arc has embraced all his wounds. The night his parents were murdered is crucial to his story arc and his character development. Bruce could have gone haywire and chosen the path of destruction, given he had billions at his disposal. He climbed out of the rut, beat against the currents, embraced his pain and became Batman.
The same can't be said for the Joker. His story is steeped in a tragedy like Batman's. Instead of climbing out of the rut he chose the life of a supervillain. The Joker didn't embrace his pain, but he adopted a violent defense mechanism to deal with it.