Let's put it this way: Each episode of Gurren Lagann takes all the action from five episodes of Naruto, and squashes it into one episode.
Both series are humorous action adventures with a young protagonist and a coming of age theme. Both series focus heavily on FIGHTAN! The difference is that Gurren Lagann has superior storytelling and characterisation, as well as much more intensely action filled fight sequences.
If you like Naruto, then yes, I can almost guarantee you'll like Gurren Lagann even better.