no problem! I'm sure there are other options... I just have never felt comfortable working on multiple machines unless it was a "last resort" situation. Haven't been there yet though.
I think the improvements from v4 to v5 are like going from a BMX to a 18-speed. Both are great, but v5 has a lot of major improvements that increases productivity and efficiency. It really depends on the designer and what tools they/you like to use. Many aspects are still the same as the general UI hasn't been modified a whole lot... but "little" things like a new toolbar for cleaning up the number labels, and the "block" tool which is a significant addition, in my eyes.
They completely redesigned the block tool to where it's so useful that I use it for any or every block/diamond/rhombus I need to create, as well as the occasional rows of lines or columns. (can't really explain without a visual example, but you'll see what I mean eventually.) I also really like the production sheet option and the way we can use that to enter the text box info.
Most everything else is generally the same... some other technical internal stuff was cleaned up to improve the software's performance but I couldn't begin to tell you about that.
As for the iPad and all that, I actually made a short video
showing a way to use it as a drill tech. I didn't think about it until I made the video but I kinda wish I could be a guy in the box using it like this. What a great tool.
I know that many people already have found ways to make it work or will perhaps develop a specific application... but since there are already adequate applications out there, I assume that the app GoodReader will work out just fine for everyone.