I was actually very surprised by the lack of good blogging software for the iPad. The Wordpress app isn't all that friendly, especially if you're trying to use it offline. Without a network connection, it pops up six or seven dialogs in a row complaining about the lack of connectivity. Really quite frustrating. The interface is clumsy, which is frustrating.
And of course, now that I've finished reading all of this, a new release of the WordPress app is available. It still shows the same XMLRPC error dialog I saw before. Perhaps it is more stable in other areas, but I'm not that impressed. It's also awkward to select the scheduling for a given post. Every time I push a post to WordPress, either as an online draft, or a post scheduled in the future, I always get the impression that it is being posted immediately. Not a good feeling.
The other contender is BlogPress, which I have to admit, seems to be much more polished. It clearly separates local drafts, online drafts, and published posts. The interface for selecting tags for the post is a little awkward, but it's there. Selecting the save button will provide you with a popup dialog showing how you want to save the post (ie, publish, save as online draft, etc). Now, unlike the WordPress app, BlogPress does not provide any ability to see or moderate comments on your blog. Not really a big deal, but something that would be nice. Another difference is that BlogPress doesn't cache your online content. If you disconnect from the internet, you will be unable to read or edit anything that is stored online, even in draft form. I've also encountered several crashes while attempting to post entries as online drafts. Thankfully, there does not appear to be any data loss, as the posts do appear online, but it doesn't reflect well on the app.
There is also MacJournal, from Mariner software. From the reviews I've read, it lacks considerable functionality from the desktop, and it eats whitespace.
I was quite surprised that there weren't more blogging apps available for the iPad. In particular, I was hoping for MarsEdit, which is a really popular client on the Mac. The Red Sweater Software forum has posts indicating that other things keep coming up. I can appreciate the need to keep existing customers happy, by maintaining his existing software, but I am surprised that he hasn't made a port to the iPad yet. I obviously don't know what his codebase looks like, but I would hope that at least parts of it would be portable to the iPad. Opening up a whole new market would seem to be a worthwhile endeavor, especially while there is not much in the way of serious competition.
What I can say is that with the Apple Wireless Keyboard, or any other bluetooth keyboard, typing on the iPad is just as fast as using a laptop or desktop machine. The iPad is a serious contender for those who wish to write, although the web browser fails to impress when using the WordPress web interface. Scrolling... well, let's just say that the Mobile Safari kind of fails to scroll on pages where I seem to think that it should. Also, something about the WordPress editing page leaves the browser with some fairly serious rendering issues, as in completely failing to render text in the editing area.
For now, BlogPress seems to be the way to go, despite the glitches.