@KiShiDo:
Croc was harder to fight cuz he was a logia and Luffy didn't know his weakness at first. But then he beats him clean.
Did you look at the other two fights? There was no beating him clean at all. They were still hard fights.
Imagine him using Gear 2 against Croc after realizing his water weakness. Croc = KO.
I think this is unfair. I do believe that Ennies Lobby Luffy is stronger than the Luffy that fought Crocodile. If Luffy and crew had the strength that they had at Ennies Lobby in Alabasta, then the fights certainly wouldn't have been hard at all.
He and Enel could barely take Luffy's base attacks. And Lucci laughed about them.
From my observations, Crocodile seemed to take Luffy's hits better than Enel did.
@Luffy:
You bring up excellent points, however, the thing is that clinches it for me is that Luffy HAD to use them. When he fought Crocodile, he didn't need to use Gears. True, he barely won but he still managed to beat him without using Gears. Now in Luffy vs Lucci, when Luffy fought him in base mode, he was clearly outmatched and over-powered. He couldn't even hold a candle to him in terms of physical combat. I truly believe that without his gears, Luffy WOULD have lost and it's only thanks to them that he managed to win. Ane he BARELY won even with them. And they gave him a huge increase in power, as well.
Once again, the Alabasta arc Luffy didn't have gears and certainly didn't think of using them. He just fought his hardest the best way he knew how. Same thing about Luffy being stronger during Ennies Lobby than in Alabasta. However, there is no doubt that he was outmatched without Gears against Lucci.
Base Luffy's physical powers were more than a match for Crocodile yet didn't stand a chance against Lucci's and even with his power-ups he still barely managed to beat him. To me, that's why Lucci gave the harder fight.
With this, I'll agree that physically Luffy could match and overcome Crocodile. However, other things went into the match. Certainly, Luffy's fight against Lucci the second time was extremely difficult and the most fierce that he had had yet. However, he was never actually beaten to death's door fully. The first time, he was stabbed in the chest and thrown out of the building. However, he was still fully conscious and could get out of the situation on his own. The second time, he was beaten severely, but if left alone, he would have still lived.
In all three fights, Luffy would have died against Crocodile so what I really think is that different terms are in need here. Physically and blow for blow, Lucci wins in giving Luffy the harder time. However, Crocodile was presented as deadlier in the fights against Luffy. So I think it would be that Lucci gave Luffy a harder fight, but Crocodile gave him a deadlier one. Also, I think both of them are pretty close to each other in giving Luffy a difficult fight.
Sorry if it was long, but that's my two cents on the matter. Anyway, as I said before, many people liked Lucci for his interesting fighting style and how he gave Luffy a good fight of two people just exchanging blows. Something like that.