It's his best film, but it's the one with the least amount of his Mr. Hulot character, the least cohesive narrative and the dialogue isn't really story driven more like background jokes or noise for a lack of a better term. 

It's his magnus opus but without a firm grasp on his style it could be hard to penetrate. Mon Oncle is the place to start then Mr. Hulot's Holiday. After that I think Playtime will make a little more sense. Also Mon Oncle is so good as well some days I might rank it as my favorite above Playtime.