The 6 Bg5 Nardojf is very crazy for white too The RR is very much more controlled, especially the (vaguely) modern f3 based stuff.
(That's rather like 6 Be3 vs the Nardojf actually.).

The crazy anti Classical lines nearly all start 6 Bc4.

I think Ako nailed it; 9.Nxc6! takes a lot of the fun out of Black's position.  Then all of the other lines where Black accepts doubled f-pawns are certainly not a walk in the park, either.  Yermolinsky has written a lot about the Rauzer in his book Road to Chess Improvement, and of course in his book on the Classical Sicilian.  I think his Classical Sicilian book is good, but be forewarned: if you buy it wanting to play the line as Black, you will become very depressed.   

In principle I want to like Black's side of the Classical, but I couldn't find anything I liked against the Rauzer.  Still playable if those doubled f-pawns are to your liking, of course.

Rauser has been difficult for black since 6.Bg5 e6 7.Qd2 a6 8.0-0-0 h6 was spoilt by 9.Nxc6!

I haven't found a single line that is rational for black. 8.-Bd7, e.g., leads to ugly positions that are easy for white and difficult for black.

Perhaps 7.-Be7 could be considered again? CP January 2012: Shirov-Jobava  6...e6 7 Qd2 Be7 8 0-0-0 0-0 9 f4 Nxd4 10 Qxd4 Qa5 11 Bc4 Rd8 and black survived. What is overall status of 7.-Be7?

Perhaps the Najdorf is more popular at the top, but for club players I think the Classical Sicilian would be a better practical choice. More likely than not, the white player has no idea what is going on in the double f-pawn positions. The same of course cannot be said when White just throws the pawns down his kingside, as in the Najdorf.

I also think it has something to do with Bg5 against classical but more for theoretical reasons, white players need less theoretical knowledge in Bg5 classical than in both Englisch attack Najdorf or in Bg5 Najdorf where both sides needs to know lots of concrete moves.

Gilchrist is a legend wrote on 12/30/11 at 08:59:48:


7...Qb6: 10.e5 gives black a hard time
7...Be7: Perenyi Attack with 16.Rg1 favours white
7...h6: 11.Be2 covering the knight jump to g4 in the Browne System
6...Nbd7: 7.Bc4 suggested by Kasparov in his Najdorf DVD

I think they are all playable for black, of course, but not clearly better than the Kozul line of the Richter-Rauzer as the Russian School inclination to play the Classical Sicilian shows.

Gilchrist is a legend wrote on 12/29/11 at 20:13:44:

What 6.Bg5 Najdorf line gives black better winning chances than, for instance, Kozul's Rauzer with Bd7, b5 & Qb6?

The Rauzer (6. Bg5 against Classical) effectively stopped any popularity associated with the Classical. The positions can become quite difficult to win, or even draw against quality opposition. Not so with the Najdorf.