Where The Life Aquatic is meandering and slight, I found The Darjeeling Limited to be economic and affecting. It gets accused of favoring aesthetic over story, which can sometimes be the case with Anderson's films.
In Darjeeling though, I think Anderson broke new ground on comfortably letting the two coexist and support each other. The glasses a character wears or the music one plays when seducing a woman are just as important as the words that come out of their mouth. Instead of being distracting or extravagant (I'm looking at you, stop-motion sea animals), these details helped flesh out the story. Sometimes it emphasized themes, other times it revealed exposition. Holly Harry touched on all of this earlier in the thread.
I also found the dynamic between the three brothers to be much more convincing than the family dynamic of The Royal Tenebaums. Wilson, Brody, and Schwartzman achieve a flowing rhythm that is instantly recognizable to anyone who grew up in a family of siblings who fight, keep secrets, and struggle to separate themselves from each other.
All in all, I think this is the most refined and mature movie Anderson has made. It distills all of his strengths (is there any other country more perfectly suited to his busy aesthetic than India?), and the brisk 91-minute running time ensures that each mannerism, quirk, object, and line pushes the narrative forward. Some of the themes and ideas are a little stale from the Anderson canon, but they've never been packaged this well.
I also threw it under "Misunderstood" because Adam and Matty weren't fans. In their review (and I may not remember the phrasing exactly) Matty said that he wished Anderson would return to the less-affluent characters and worlds of Bottle Rocket. I've also heard this complaint about Darjeeling from other folks. I understand where it is coming from, but I completely disagree. The last thing we need is another rich white guy making a small film about folks on the lowest rung of the economic totem pole. I'd rather he write about what he knows, and frankly he knows the spoiled westerner well. The real trick was being able to make fun of these characters (“Those kids are laughing at us....I love these people”), while still making them sympathetic and compelling. I found this story of death, travel and family engaging and wise, so it worked for me.