Tales of Monkey Island: is it worth it? Does it live up to the legacy? I entrust the expenditure of my hard-earned pieces o' eight to your infinite adventure gaming wisdom. Edify me, O Great One.
Overall, yes, it's very good. Is it up to the standard of the earlier games? It depends whether you're talking about how good the originals were, or how well you remember them being. Can any game live up to that? Probably not.
Next to how good the original games ACTUALLY are, yes, they're more than worthy of the name. They have a very different style - much more focus on characterisation and plot, taking a lighter approach to the world, but often a darker one when it comes to the actual plot events. The big storyline (tracking down a magic sea sponge) is incredibly silly, but many of the smaller details are actually pretty dark. Bad stuff happens, Guybrush pulls more than a few dickish moves, and the characters get a lot of time to get to know each other pretty well, forge new relationships, and generally be much more interesting than they were in the original games. After playing ToMI, it's almost a shock to go back and see just how bland Guybrush often was in the original games. Telltale did a great job bringing him back.
In the interests of unfairness, there are things I don't like. I wish the look wasn't quite so cartoony, Telltale still has a tendency to abuse the same couple of puzzle structures to the point of insanity. Elaine is still rubbish. And I'm not wild about a few additions to the world, notably a recurring villain called the Marquis de Singe, and the extra fantastical elements of talking animals and a mermaid civilisation.
None of those are deal-breakers though, and for the most part I had a great time playing it. It's funny, sharply written, some of the puzzle design is fantastic, and it has Morgan LeFlay in it. The later episodes show clear signs of time pressure cracking down, but tend to make up for it with the big set-pieces. The final couple of episodes especially have some really awesome MI moments moments to look forward to.
(As with all episodic games though, don't try to play through the whole thing in one sitting. There is repetition, especially in the reuse of some very tedious jungle sets, and there's a LOT of padding in each individual episode. Play one, give it a break, then go back to the next. That's how the story was meant to be experienced, and it does some really clever things with the time gaps that structure allows for, especially in the Morgan/Guybrush and Guybrush/LeChuck relationships. Yes, there is one.)
Short answer: Yes, I recommend at least giving them a shot. They're really good adventures in their own right, an excellent next chapter in the series, and as long as you don't go in expecting too much, I think you'll enjoy them.

