I'm extremely happy to report that they all work great, but Stainless is looking really cool. In particular the large Quick Icons are easy to click with your finger, and the depressed CSS active state of it and other buttons gives you the proper user feedback you'd expect. Also, the sidebar component list that's featured in many of our admin templates is very useful, and similar to sidebar links you'll find in many iPad apps being released. The QuickAdd and MyEditor selectboxes (shown in screenshots) also work very well. Check out the screenshots below.
We're really excited that our modern web practices are translating well on devices like the iPad and we'll continue to push them. Look for some iPad specific updates in existing admin templates/extensions and possibly some iPad specific releases soon...
We'll also have a Stainless Beta release coming soon!