One of the reasons I wanted to switch from my Sony reader was the lack of technical books unfortunately. Nook is my #1 choice right now precisely because of the fact that I can transfer my entire Sony library to the Nook - go epub!
As far as PDF discussions, maybe I should've worded my question differently. I've read all the discussions about standard PDF documents, and understand the limitations of the Nook and other devices. However, since Borders is an ebook store, I am hoping that maybe the PDF versions they are selling are formated to better deal with smaller ebook reader screens that your typical PDF manual, etc. I guess the only way is to actually get something cheap from them and try it out.