But it depends of the person who uses it. Because Luffy is stronger than Ace.

Inherently, any Logia should be more powerful than almost any Paramecia (obviously there are exceptions, like the Gura Gura No Mi, for instance). However, Luffy is the main character, therefore has plot armour. Also, Oda is really creative with the way Luffy uses the Gomu Gomu No Mi.

I'd pick this one easily given the choice. Ace was just unlucky he got Blackbeard as an opponent.