I was wondering what is worth more in terms of back links to increase my PR . 1 backlink with PR 4 or 4 backlinks with PR 2 ?
It depends on the number of outgoing links on the page. A page with 10 outgoing links passes 1/10th the PR compared to a page with a single link. Each increase in PR requires approximately 6X the amount of links, so everything being equal - a single PR4 would pass more PR. To further complicate matters, PR is rounded down. A PR 2.99 is going to show as PR2 in your toolbar. Forget about PR if you are trying to increase your rankings. You need relevant links from authority sites.
focus on building quality links to your sites regardless of PR. PR will come over time but it is the quality of backlinks that are important. if you get a relevant backlink form a quality sites that is PR2, it is lot better than getting a link from PR4 irrelevant site.
Can you define quality backlink because it is a bit confusing. DP is a good quality site but not solely in my own niche. What about if you have a Financial site that talks about money, and you have some links here? As we all know DP is about SEO and other stuff and this site is not just about Financials. Would the quality of backlinks here matter? What do you think?