1. Theoretically 3.d5 is the only move that allows white to keep an advantage after 1. d4 Nf6 2. c4 c5. All other choices are lessor options for White.
2. Central pressure is more powerful than wing pressure. Black gets direct pressure agaisnt the White king in the Kasparov/Vaganian Gambit.
There is an excellent piece on this gambit in the Dvoretsky manual, Positional Play, by Dvoretsky and Yususpov.
I usually start to salivate when people play 3.Nf3 in these positions, but I am an attacking player (why else would I be punting 2. ...c5!?). The attacks Black gets in this line are more direct and come faster than anything Black gets in the Benko. The Benko is all about being able to play a rook endgame, down a pawn, but with active rooks for compensation.
The Kasparov Gambit is all about punishing white for choosing to play passively.
Are we talking about the same thing? Games Explorer didn't give me the name.
1.d4 Nf6 2.c4 c5 3.Nf3 cxd4 4.Nxd4 e5 5.Nb5 d5 6.cxd5 Bc5
I agree that 3.d5 is the most serious try for an advantage. I don't know the Benko or the Benoni very well so I don't play it.
While it is more passive than the d5 move, I think it's a bit reaching to say that black is punishing white for his passive play. This 4... e5 move is one that would be a perfect target for a Rybka III analysis. For that matter, I would think that Gonnosuke has an opinion on this line, since he is always attacking no matter how sound the attack is. :-)
I own that Dvoretsky book, I'll take a look.
I took lessons from Mr. Dvoretsky. An amazing trainer.
The most feared defense against 1.d4 is the nimzo-indian. Its the easyist to learn and understand its concepts as Black.