With all these comments on the PDF and reading offline... I guess I don't get it. Why go through the trouble of logging in and extra expense of printing PDF's when you already have a hard copy via the magazine?
Two big reasons.
On a day-by-day basis, I can be anywhere and suddenly have time to kill while I'm waiting for something to happen. Lots of times I'm in a basement where I have a laptop running but my wi-fi card doesn't work for an internet connection. I even run into that on rooftops or in the middle of building where concrete and steel interfere with a wireless internet connection. A PDF download means I can spend the time I'd like to browsing through each issue when the time presents itself.
The second is access to the issues when traveling and camped out in an area that doesn't have any internet access (with a potential truck problem that you need info on). That speaks for itself.
I spent a few minutes in the digital magazine area playing with it. I could print pages that interested me and convert them to my own PDF's as needed, but aside from being time-consuming, it takes the enjoyment out of going through sections of each issue page-by-page, seeing things I didn't see the first few times through. That's the enjoyment of a magazine.
Lastly, I plain don't have the time around the house to sit and read the four magazines I subscribe to. 3/4's of the WSJ's in my drive don't get opened.
As it is, I may only see 5% of an issue since I'm too busy when I'm at home. Sadly, I might go three or four issues of TDR without ever opening them. A PDF on my iTouch or on a thumb-drive gives me access to read when the time presents itself and an internet connection isn't in front of me. That's what works for me. Carrying around magazines in my back pocket isn't an option.
A downloadable PDF would allow me pass on the printed issue and save the cost of postage and printing, and help keep TDR's costs down. Any thing less, and I'm still going to want a hard copy for when I don't have an internet connection.