difference between closed sicilian and grand prix

It seems like the closed sicilian and grand prix (with 2 Nc3) are very similar. I was wondering if someone might be able to help me understand if there are significant differences between the types of plans used in these openings.

It is my understanding that in the Grand Prix Attack, White's f1 bishop develops to c4 or b5, and White plays an early f4. In the Closed Sicilian, White fianchettos his f1 bishop and f4 can be delayed.

Thanks. I'm still not sure which one I would prefer myself, is the style of play drastically different between them? Is one of them easier to learn?

In my experience the Grand Prix attack is easy to learn and play. Furthermore there seem to be more instructional materials about it than for the closed Sicilian.

I used to play the Smith-Morra Gambit against the Sicilian. I played this for a little over a year, now I've switched to the Grand Prix. What I like about the Grand Prix attack compared to the Smith-Morra is for one, there's a whole lot less theory (although of course there still is some), but what I particularly like is that you're not committed to any type of play. You can go for the caveman attack, or you can play positionally, particularly if you're able to double Black's c-pawns. When the position is right for the "attack" plan of the Grand Prix, it's extremely easy to carry out. Nigel Davies said on his chessbase DVD "you could teach this plan to a six year old and he'd be dangerous with it". Roman Dzindzichashvili, Eugene Perelshteyn, and Gawain Jones have also authored excellent books and DVDs on the Grand Prix.

I believe the closed Sicilian to be very good also. Although I've not personally played it.

Thank you that's very helpful advice.

In the Closed Sicilian White gets a similar slow build-up to a kingside attack as in the King's Indian Attack, though in the Closed Sicilian the big pawn break is usually f5.

It was Spassky's go-to line against the Sicilian and he did well with it. Though its current statistics aren't impressive, the Closed is still a solid, potent system which can yield a strong attack, so Black had better be active.

Thanks everyone.