iBooks is a great app. Slandered by many, written off as inferior to Amazon's Kindle, it actually turns out to be a really good app for consuming text. Not only that, the recent upgrade to allow PDF reading opens up whole new classes of documents for iPad consumption - technical documents (many companies publish specifications or design notes in PDF), sales brochures, self-published books, work manuals, magazines, newsletters; the list is endless.
The bookstore is not so good, but it does at least appear to be improving quickly. When I first picked up my iPad there were very few titles available (no Tolkien, for example, and almost none of the current authors I like to read) but this is being rectified (Tolkien is now well, if not comprehensively, represented) and I'm almost ready to make my first purchase.
On that note, it's interesting that lots of titles are priced at or above their Amazon price. It might be that publishers are simply hiking eBook prices to hit the early adopters as hard as possible but I wonder also if this indicates extremely low distribution costs for physical books (if a paperback that retails at £7.99 costs only £1.50, say, to print and ship, there's not much room to lower costs for the eBook version).
In fact, is an eBook actually a book at all? Sounds like a daft question, but in the UK books are exempt from VAT, software and online services are not, so it's actually a very important question. If eBooks aren't defined as books by HMRC (who are, I think, responsible for collecting VAT) then they're subject to a sales tax of 17.5% tax that doesn't affect their physical counterparts and might, therefore, explain some of the price difference.
So, are there any bargains on Apple's bookstore? Well, sort of. Peter V. Brett's The Painted Man, for example, is available for £3.99, matching Amazon's paperback price (excluding shipping, of course). Bram Stoker's Dracula is free (and if you've never read it please check it out - it's an excellent example of slow-burning tension and horror) or, if you prefer to pay for your out-of-copyright literature, £4.99 or £5.49. Most books appear not to be price competitive with their physical counterparts so you're paying for convenience; personal circumstances will determine the value of convenience.
Conclusion? It's a good start. The bookstore is reasonably well stocked (much better, it has to be said, than Amazon's UK Kindle store, which is non-existent - you have to buy your Kindle books from the US in dollars) with over 26,000 titles, the prices are high but convenience is considerable and delivery immediate. As new books are added and older texts fall in price, it will become, I suspect, a serious force, especially in the UK while Amazon refuse to play.