Ok, here's my perspective on this whole thing. I started out getting backlinks before I'd ever heard of Angela Edwards. My technique was following the backlink trails of professional spammers. I knew these guys were pro because they ranked very well for their keywords.
These guys all focused on high PR pages (not domains), to maximise the flow of link juice from that site to their own site. One guy I found had nothing below PR4. They'd spent effort finding these high PR pages where they could link drop (********) and I was following in their footsteps, jacking high PR backlinks into my sites and watching them rocket up the SERPS.
Then, I hear about something called Angela's Backlinks. Apparently this person seems to think that having a link on a PR N/A page of a PR7 domain is a great thing. It really isn't. Let me go into detail.
Page rank is a general approximation of how much link juice a page has flowing into it. A PR n/a literally means that the page has link juice of near zero. So, the only value that could come from it would be the authority effect.
Now, I acknowledge this authority effect exists, but I don't feel it's as important as a lot of other people do. Take .edu sites, for example. Google has officially stated that there's nothing magical about them. They just tend to be more powerful because they have been around longer / have good content, so more sites link to them. In other words, authority effect may just be a byword for the domain having a lot of aged inbound links.
My argument boils down to this: if page rank is an accurate measure of link juice, and (after keyword optimisation) link juice determines SERP position, PR n/a pages are comparatively worthless for backlinks.
I spied out Angela Edwards's websites (she has quite a number of them). The backlink profiles are chock full of exactly the sort of pages I've been describing that I and other spammers use - high PR pages. If you want backlinks, look there. Exchanging money for Angela's list of PR n/a pages couldn't be more foolish in my humble opinion.