I can confidently say I've taken sims on vacations to all three destinations over the years, and I think Twikki Island has the most to offer. The beaches alone and all the interactions that come with them make it stand apart from both Takemizu Village and Three Lakes. Add in the hula dance (a plague unto my sims, always), fire dancing, pirate ships, and ancient ruins, and it's easily the one that draws the eye and the attention of the three, for me. Like Terula mentioned above, the vacation spots all seem to cater towards adults and elders, leaving very little for kids. Mind you, I've brought exactly one sim child on vacation before, but I think that's largely because I'm left with a sense of uncertainty when I think about having kids at most of the locations. At least Twikki Island has its beaches, where kids can play in the sand and swim in the ocean and hunt for shells just as well as their parents. The other spots seem to be lacking in that versatility.
My second favorite is Three Lakes. It seems to me that Three Lakes has the next best number of activities, though again, they're mostly geared towards adults. I'm a backpacker in real life, so the charm of being outdoors is immediately a draw. I love that my sims can camp out in tents, and I don't think I've ever made use of the lodges and hotels at Three Lakes because I think it's so lovely to watch the sims fish at the lake, duck inside the tent for a nap, then sit around a campfire. Three Lakes has my favorite custom food items -- the flapjacks especially. I like the log rolling and ax throwing activities, it's just -- again, not much for
everyone to enjoy. I also can't justify sending any of my sims from Riverblossom Hills here because they basically fish and shoot the breeze in the wilderness every day already.
Now, I actually like all of the vacation spots, but I find Takemizu is my least favorite. I really enjoy the hot springs and spa, as well as the zen gardens and tea houses, but...that's basically all there is to do there. I sent a whole family there and they basically just stayed holed up inside their hotel, because I chose the one with a tea table in the main patio. I find myself at a loss for what to do in Takemizu just about every time a sim goes to visit, and I always choose the shortest vacation time when the sim wants to go on a Far East vacation, because there's just not much to see. Part of me wants to remodel the whole vacation hood and add in some more modern fixtures found in Japan like video arcades, karaoke bars, and sushi restaurants, but it can be kind of an overwhelming task to approach with the size of the place and the number of lots.
Every destination has its attractions. I guess it all just depends on the player and the personality of the sim who wants to go.