[richman]

Gee, I think it will depend on the technical pdf's that you have if it will work ok for you. If they have lots of diagrams and flow charts and all types of stuff like that, I think it will not work that great. I think it will be hit and miss.
You can probably convert them as others are saying , but , just go into this prs-505 ereader as being best for reading regular books and "searchable" pdf's . If it's a scanned book it will not work that great at all.
Just think of pdf in 6 inch format and you will see that most pdf's are in much larger format and not tiny format. Conversation programs will work to re-flow it but just understand the limitations before you accept the package if that is your primary purpose. Most of my medical stuff will not work with prs-505 , but will work in my acer 8.9 netbook. So I use some of the medical stuff that works on my prs-505 and my pleasure reading on prs-505 and newspapers on prs-505 using calibre. And use my netbook for more involved stuff. I love the prs-505 and bought 2 of them , I like it so much, and I do have netbook and laptop. So go into this with your eyes OPEN and you will love it. If you have special needs , I think you are doing a good job of finding out before hand if this will work for you. Read lots of stuff from this forum and other places to help you make an informed decision.
p.s. Maybe post a pdf or some file that you are wondering if it will work on prs-505 and someone here can download it to prs-505 and see if it will work. OR download calibre and convert it and see what it looks like on your computer screen when you "view" it from ICON in cailbre. You will see what it should look like in converted form. Hope that helps.