In terms of raw power, of course. However, it is more useful for finishing moves whereas G2 is better for general combat. Yes, it is.
Gear 2 while almost comparable to a shinpo, lacks any strength against more sturdier enemies and almost hits at his hearts limit thereby decreasing his vitality and life force by the end of his time limit. Then you have Gear 3 which does increase his scale and power of attacks in exchange for speed.
The fact is that it is quite possible that the increase in power obtained with the second is equivalent to the increase in Luffy's reward, that is, the gear second multiplies Luffy's base strength by 3 .
Gear Fourth and its various forms combine the best features of Gear Third and Gear Second. Luffy can move nearly as fast as Gear Second, while being able to launch attacks of the same size as Gear Third. The form's use of Armament Haki further solidifies it as stronger than its two predecessors.
Also learned by Luffy during Water 7, Gear 3 is another technique that drastically boosts Luffy's power. To use this Gear, Luffy bites his thumb and pumps air into his bones, making them huge and thus turning his limbs into those of actual Giants.
Luffy is confirmed to have overcome his weakness of shrinking when deactivating this Gear, after inflating both his arms and using "Gomu Gomu no Elephant Gatling" on Noah for a prolonged period of time and not turning into his chibi form.
Although rare, Luffy has, at times, used Gear Second and Gear Third at the same time. Luffy's attack, known as 'Gomu Gomu no Gigant Jet Shell' sees his combine the powers of the two gears.
Currently, Luffy's fifth gear is his most powerful gear as it is mentioned that it is his peak form. In this form, Luffy awakens the true powers of his devil fruit and transforms into the sun god Nika.
After entering Gear 2, Luffy uses Busoshoku Haki to harden his arm entering in Gear 2 Busō. He then stretches it back like Gomu Gomu no Bullet. When cocked back, Luffy's arm ignites, releasing a stream of fire in the process while he proceeds to deliver to his enemy a powerful flaming punch.
While all these power-ups were incredible and enabled him to take on some of the most powerful people on the seas, he didn't truly hit his peak until the Wano Country arc. In the fight against Kaido, Luffy finally tapped into what is his strongest transformation of all time and supposedly him at his peak – Gear 5.
Using Second Gear has definitely shortened Luffy's lifespan. The technique involved him pumping blood through his body at an accelerated rate in order to give himself a boost in speed and power.
How Strong Is Gear 5 Luffy? Like other Awakened Zoan fruits, Gear 5 is a drastic improvement in Luffy's strength, speed, durability, as well as an upgrade to his standard rubber powers.
Against Shanks, even if Luffy possesses weaker Haki, the Devil Fruit abilities of the Hito Hito no Mi, Model: Nika can make up for the deficit and see him emerge victorious. Currently, however, Shanks is likely stronger than Luffy, simply due to the fact that the plot demands that of him.
Luffy's Second Gear shortens his lifespan but he could beat Naruto in Sage mode. Luffy is too fast for Naruto, fast enough to dodge his Rasenshuriken. With his Jet Bazooka, he could easily throw Naruto.
However, when it boils down to it, Gear 6 is entirely speculative at this point – but with Oda's history of diverting expectation, its not clear whether or not it will ever come to fruition.
Could Luffy beat Goku in Gear Five? No, he can't. The power scaling in both verses is vastly different: one verse has gone from building to moon to planetary to solar system to low multiversal.
Conqueror's Haki is one of the rarest powers to exist in the One Piece world. Unlike the other two Haki forms, this power isn't accessible by everyone but exists within only a chosen few.
Luffy by biting into his thumb and inflating his body through his bones. With the bones growing larger and stronger, Luffy is granted immense strength, capable of shattering a Marine battleship in a single blow.
In the anime, the user of Haoshoku Haki has a dark purple aura around him. This can be seen only in Episode 723. In Episode 893 however, Haoshoku Haki has a gold sparkling effect visually similar to the Pika Pika no Mi. In the case of Roger and Whitebeard, their pupils also shine with a red glow.
Gear 5 is Luffy's pinnacle power, and he can do anything he wants in this form. Furthermore, it is mentioned that his powers are only limited by his imagination. With this gear unlocked, Luffy is said to resemble the “Warrior of Liberation” — Sun God Nika, who is said to bring smiles, joy, and freedom to the people.
Gear 5 is Luffy's new technique that is a product of Luffy's Devil Fruit, Hito Hito no Mi, Model: Nika (not Gomu Gomu no Mi)'s awakened true form. It is the peak of Luffy's power and gives the character god-like abilities – literally letting him do anything that he can imagine.
The Red Hawk technique is performed by Luffy activating Gear 2, then using his Armament Haki to coat his arm as he prepares for a standard Jet Pistol attack. By doing this, his arm ignites into flames, tremendously improving the strength and power of the attack.
At Shells Town, Luffy's Gomu Gomu no Rocket was faster than sound (343 m/s, Mach 1). The Gomu Gomu no Bazooka Luffy used to defeat Wapol on Drum was about Mach 10. Luffy did move a bit faster than lightning at Skypeia, so about Mach 1300.
Luffy has a total of 6 gears (Three being subforms of Gear 4) and are divided into four levels. These Gears have become stronger over time and give Luffy huge amounts of power.