i much like quality than quantity, but the most important you have a good quantity of quality links.. lol do i make you confused?
back link you mean one. just kidding, anyway I'll go on Quality back links because Google has an algorithm to sort those unrelated links and paid links...
The best approach is to have a mixture of different types and PRs. That looks more natural than just having a few high PR links and hardly anything else. Also, a large mixture of different types gives you some immunity to futue changes in Google's method of assigning relative values to different kinds of links.
NEVER! But that isnt to say a lot more of lesser quality cant surpass higher quality links. The key there is that there is some quality in the link. Some links have absolutely no quality or SEO benefit.
I vote for quality. 99% of my backlinks are PR3 or higher. I don't take sites below my PR (except just a half dozen or so). Has worked well so far. I could take 1000-2000 more < PR3 but don't want to chance it.
Does any the links have relevance to your site? And no I would not take either one actually. Get me a nice content partner and that is what I would rest my revenue on.
Ask everyone what the meaning of "quality" means. You get many different answers. A high quality link that has no page rank has no value (as to PR juice passing). A low quality link that is a PR 7 will have PR value. What Google wants us to do is obtain revalant links from a site that is revalant to the site being linked to. So the next question is what does "revalant" mean. For most of us, obtaining links is hard enought but "high quality" "revalant" links from a "revalant" site. This equals buying a link. And we all know this is not done... Suggestion, there are many new sites that have not been indexed by Google or havn't had a PR update applied to them. These are "PR0" sites. I will link to them for one reason, if they are a good design with good SEO concepts, that site will become a PR4 or 5 site within a year. I helped them and in return, they will help me. Oh, it helps that they are also within you field or topic.
Although quantity of backlinks can help your site but it is more appreciated when you can have a quality backlinks.
...a site with lesser number of links but all are of good quality can easily outrank a site with tons of unrelated links