If you're a WDW regular, you may be underwhelmed by HK. I enjoyed it, but you need to go in expecting a small park with some serious cultural differences, and just enjoy it for what it is.
The most unique, exciting attraction would undoubtedly be Grizzly Gulch. I plan to head straight there on my next trip!
There are other relatively unique aspects. I think Stitch Live is unique to HK, and the Golden Mickeys, unless you've been on
DCL. The Jungle Cruise has cool fire/water effects at the end, and was enjoyable, and I thought our English speaking skipper did a great job! But I have heard of people who have problems with the language barrier. Tarzan's Treehouse is a fun place to explore, pretty much the same as the Californian one but being on an island in the middle of the Jungle Cruise adds a bit of extra atmosphere. Our raft on the way back over the river got taken over by pirates, which was an unexpected bit of extra magic! We didn't get to see The Lion King, but I hear it's a bit different from WDW.
We also enjoyed Buzz Lightyear, Space Mountain, Winnie the Pooh and Philharmagic, but they were pretty much the same as the other parks. Dumbo was the same too of course.
Although they're not 'attractions' as such (and your DS may not find it exciting), the scenery and castle were different and beautiful with the hills in the background. The shops also had some different things to look at - there was a very cool doll house fully furnished with Disney touches.