Super System II is good. It's well written and contain much that is not found here at PokerStrategy. For instance, the chapter on 2-7 triple draw and Mike Caros chapter on diverse topics.
The chapter on NL Holde'm can be described as "dangerous". It applies mostly to very deep stack play and presupposes that you know the math already. (Doyle also writes that he is really struggling to win in shortstack play.)
The label "dangerous" should be attached since it is easy to get the impression that you only have to make big bets on multiple streets and see your opponents fold. The text doesn't really say that you should. There are some pretty subtle points about different board textures and stuff like that if that is what you are looking for. How to play AA and 76s is handled in extreme depth.
The part about playing your rushes is especially dangerous since the unwary reader migh get the impression that you should play because you are especially lucky at the moment. The point is rather that you should take advantage of the fact that your opponents may be temporarily intimidated. Surely, such players as Durr, Isildur and other *urrs have this vital ingredient in their game.
The main difference in strategy between the "standard lines" of basic pokerstrategy.com articles and Doyles lines is probably the donkbet on the flop versus the check-raise. Doyle is probably correct in advocating the big donk if the stacks are very deep (>>100BB) but not with typical online stacks. Balancing ranges is not explicit in his lines.
Outdated?
Yes, maybe, but Brunson has held his own at the real nosebleed tables for some time now and I guess he holds more WSOP bracelets than most PokerStrategy members. It's difficult to point out much that is downright wrong.
/Johan =