He ain't Moysie so that speaks for him.
I said a bit about him in the United thread.
LVB is a concept coach. He will install a modern training regime, aim for a cultivated football style and not be shy of using youngstars. Whether he will actually get super results week in week out remains to be seen. Bayern fans for example will probably think positively of him now in hindsight because he promoted youth like Müller, converted Schweinsteiger from a winger into a midfielder and generally changed their playing style. He left behind some lasting and positive changes. However he also got sacked for almost missing out on the CL - which would've been quite an achievement in Bundesliga with Bayern - and had set up one of the funniest defenses in the league. As a United fan you should remember how lucky Bayern were after the first half 3 goal onslaught at Old Trafford and then Rafael's red card and Robben's volley happened. And that season was actually his better one, despite relying on Robben so much.
His second stint at Barca was a catastrophe and he failed to qualify for WC 2002 with Netherlands. His CV isn't actually that great tbh but he's still regarded highly because like with Bielsa it isn't always about the results with van Gaal. To give you an idea what I mean. I wouldn't be surprised if next season you finish 3th or 4th which will obviously be a huge success compared to last season. But the season after you will stagnate, maybe even just about reach 4th in a turbulent season and get owned in the Champions League quarters which will result in van Gaal having a public go at the Glazers, falling out with Rooney, punching a journalist and then getting sacked. Yet his successor will walk the league and possibly even win the CL a few seasons later with a modern 4-2-3-1 or 4-3-3 system that van Gaal will have left behind with a few youngstars leading the team. That would be a typical van Gaal scenario. Does that make sense?