I am in the middle of the road whether to use jQuery UI or Scriptaculous for drag and drop. I am using Ruby on Rails, and Scriptaculous support in Ruby on Rails is superb with the existence of scriptaculous_helper.rb. But I have already use jQuery for the ajax and DOM manipulation. I do not mind to use scriptaculous since we can use jQuery.noConflict() in the code. I also kind of get the impression that scriptaculous drag and drop is better than jQuery UI drag and drop based on the online demos.
So back to the original question, which one would you recommend as a drag and drop library and which one do you think is better than the other? Scriptaculous or jQuery UI?
I've been using jQuery UI's drag & drop features and I'm pretty happy with them. Overall, they seem very well-rounded – for example, if you drag toward the top of the viewport, the page automatically scrolls up, just like users expect.
If you're already using jQuery (but not Scriptaculous), why add the weight of an additional JS framework? Bytes do count, and the more you can slim down your client-side script, the faster your app will run.