Is it good for technical books - since the page turn speed is apparently very slow? Will the iPad be better for this?
The page turn speed is not fast, but since I was used to it from my previous e-ink device I don't find it too much of a bother. The thing that you lose from a physical book is the ability to scan quickly to a particular section that you then drill down to the page you want. With e-ink you guess the approximate area and then guess a couple of more times until you get to the right page. The biggest "fix" that could be provided in this case would be for hyperlinks within the doc to work so that you could bounce from the table of contents or index to a specific page. At least with the DX I can actually go to the page I want though, with reformatted docs on a smaller display (like the use case for the OP software) there was no match between the original page numbers and the actual page number on the reader, so it was a real PITA.
Short version: if you read technical docs or papers in PDF format do not consider anything smaller than a DX or iRex.
They both suck for this application. Because their screen size is smaller than the page of the PDFs, you are left with zooming in and out (a feature which is new to the Kindle). This however leaves something to be desired as far as the reading experience goes.
My coworker owns a Kindle DX and it does much, much better at rendering technical PDFs and or technical books.
I also think the iPad will be very good at reading technical books as well. Their diagrams and code snippets will render beautifully and zooming is an altogether different experience (much more enjoyable).
So, I would definitely go with either the DX or hold out for the iPad.
I own a DX & I hate to say it, but yeah, probably. The page speed does hurt. You have to decide if it's more important than the e-ink screen.
I personally wouldn't trade my DX, but I think many people will want to watch movies & check email instead of only reading pdfs for extended periods.