iBooks on iPad results:
Hebrew on the iPad looks just great.
The text is displayed perfectly including styles etc. and it's fun to read.
The only problem I found with the iBooks application is that when viewing the book in horizontal mode (two pages view), the pages order is wrong

and is displayed left to right. It's annoying.
Another small issue is that the page turn animation is the other way around (it looks like the pages are being turned the "English" way...)
Below are a few screen captures:
1) TOC in Vertical mode
2) Cover and TOC in horizontal mode. The pages order is left to right which is wrong.
3) Main text area in vertical mode
4) Main text area in vertical mode. The text includes punctuations
5) Main text area in horizontal mode. The pages order is left to right which is wrong.