Let's put it this way. If you can't figure the interface out in the first 2 minutes, you're brain dead. My HD20GA7 has the single most intuitive interface I've ever seen. Ipods are touted as having a good interface; I think they're rubbish, and next to this, they can't compare.
You have a 4-way d-pad that's bound to context-sensitive keys, together with a central key. The screen shows exactly what each key is bound to at any given moment. The up/down keys also have 2 pressure settings, and let you scroll quickly or slowly and more accurately. On top of that, you have a separate volume slider, and a "home" type key like the windows start button that takes you back to the menu.
That's it really, and that's all you'll ever need. I wish other DAPs were this intuitive.
The build quality is also stellar; the unit feels every bit as expensive as it is. The screen is terrific too, but you can't really do much with it, which is a shame.
If Kenwood only bundled more features with these players, they'd sell one heck of a lot more of them overseas. As it stands, because it doesn't support all the formats that I use, because its battery life is rather poor, and because it hisses too much with the ES2, I use my X5, and I like it a lot more, though it doesn't sound as good.