I've been using the web interface on the ipad. This has forced me to learn how to cut/copy/paste, so I can deal with link and small chunks of text that I want to copy. Unfortunately, positioning the cursor for arbitrary editing is tricky at times (solvable by increasing the font size). Double unfortunately, sometimes when I'm doing a lot of thinking (like with the Amazon kindle gift post) I'll post it so only I can see it and then go back in repeatedly with edits, thus cutting down on the ETAYAs. For some reason, I can't figure out how to scroll within the body box on the ipad -- that's a big problem. There are some apps for lj clients (and multi-blog clients); I'll be experimenting with that next.
It's a helluva learning curve. I think the iPad does things pretty well; I'm wondering just how nasty some of the cheap tablets are going to be in terms of usability while writing.