A big rave for the book for this simple reason: If you want to know how to talk like a pirate, THIS is your book. The parlance of the pirate is pretty good in the Pirates of the Caribbean movies, but the lingo is better in this one. Far more authentic feeling, perhaps because it was written at a time when there really were still pirates around, not a hundred plus years after the fact. Indeed, much of what makes the Pirates of the Caribbean series so much fun was done first in Treasure Island.
Beyond the dialog, this is just a fun read. Full of adventure, danger, treasure and all the fun things of youth with a dollop of coming-of-age, morality and the search for a father figure thrown in for good measure. The novel is a fairly quick read, but it is fun throughout, with enough variation from the subsequent versions I have seen that I wasn't even certain how the plot line would unfold or the story conclude. Treasure Island is a terrific book for anyone over the age of eight, or thereabouts, who likes a good adventure story or wants to learn how to really talk like a pirate.
For an extra special treat, listen to the audiobook of the novel, read by Michael Page. It is a terrific piece of narration, one that really captures the cadence and quality of the pirates' language.