[tomsem]

KT is smaller, lighter, I find it comfortable to use without a cover (unlike my K3), and I have no plans to get a cover. Design is 'cleaner' without all those buttons, arguably less 'distracting' and looking like the PDA you might have had in the 1980's.

It is easier to select text and type (and you can type diacritics for west european languages). Navigation of Home screen and Kindle Store is easier. PDF support is significantly better (except for lack of landscape). Active Content (when available) is actually almost 'nice' (unlike most AC for button Kindles). And it has XRay. Script support is more complete: Indic scripts seem to work, Arabic and Hebrew almost work but maybe will require KF8 before R2L text layout is handled correctly.

Amazon has promised an update for some level of KF8 support, I believe they will also be adding localized UI option (like K4), plus whatever refinements they choose to add (including screen orientation option, with any luck). I think K3 has seen its last update (i.e. will never support KF8).

Web browsing should be better, but there is no equivalent of page up/down AFAICT so reading articles and scrolling Kindle Store item descriptions is a little annoying, as there are no tap zones and swiping only scrolls about a half a screen (at least the way I'm doing it, and I have tried a lot of variations).

As mewmartigan points out, you can tap or swipe in reading mode, though swipe is a good way to avoid accidentally de-referencing hyperlinks (footnotes etc.) when these are present, or to page back when holding with right hand (with thumb). Speaking of hyperlinks, those are easier to jump to (well. it requires a little too much accuracy at small text sizes, hopefully they will make hyperlink tap zones a bit larger with an update).

On the minus side, KT will probably never have margin/font/justification/screensaver hack, or image viewer, and has no 3G web browsing. It's not possible to extend selection to adjacent page, and it's not possible to select a word and then use that for search (though most people probably never discover how to do that on K3). The UI could be more polished, but the same is very much true of every Kindle to date.

I do hope everyone with a Touch is sending things to kindle-feedback. Amazon should not be allowed to think that it is perfect and complete in every way, and there's still a chance some improvements could make it into the update.