On a club level, Ferguson has indeed achieved more than Lippi. On an international level, Lippi proved his brilliance. The fact is, Ferguson didn't take as much risks as Lippi, he didn't coach a national side and chose to remain in Manure where he had everything he needed.
His tactics aren't what made him successful in contrast to Lippi. He has always had certain players that have been able to make the difference, super players, if you may. His success isn't a result of tactical brilliance but more of his players' brilliance. After this season is over, people wouldn't ask,: Where would Manure be ithout Fergie" but would probably ask,"Where would Manure be without Ronaldo".
To me, Lippi is a better coach because his tactics and coaching were a huge part of why Itay won the WC. He didn't have a player that could run circles around a defense and finish off the game for you, he constructed a solid, compact team that were disciplined and mentaly strong enough to win. That to me, is why Lippi is a masterclass.