Using PageRank as an importance matrix is extremely bad for SEO these days.
Google has introduced many algorithms to their engine as well as the likes of Panda and Penguin, it used to be the case that getting high PR links were gold but nowadays there are hundreds of other factors to take in and I believe no matrix online will be able to tell you this information and one of the reason I believe that you use monitor your links and value you them yourself.
What makes a good link?
It's about how relevant your link is the page that you have got, for example: if your site is about Motorbikes getting a PR 5 link from a site about Pets will pretty much do nothing in terms of your rankings, it may however increase your page rank and trust but other than that I believe these types of links no longer actually benefit, this is apart of selling links and spam links clamp down by Google.
As you know Google is pretty good at working out what pages are all about, if you have a page that is primary talking about 12 value engines for motorbikes and then gain a link from another site that is about 16 value engines then I believe that this would increase your rankings on terms of engines, now if you were to a direct 12v to 12v link then this would be the best situation as not only are your pages extremely on topic your likely to get direct traffic which in turn could increase your backlinks from others.
Now the problem is Google knows this, but does the likes of these backlink monitoring matrices? Sadly, I've seen no evidence to support they actually use page contents relevance within their matrices, the best I seen is Majestic SEO, and Moz, but these use Trust/Authority Matrix's while these are a good indication what a good link is, if your pages are not relevant then the matrix is no good.
I'm not saying to ignore PR but it should treated as a bonus
In no way am I saying that high PR pages are pointless, but I would rather a PR1 that is on topic than a PR5 that is off topic, because of the algorithms that Google has introduced. If you land a backlink that is on topic with high PR then its better than a low PR (Not always, but a lot of the times) It's important to note about Authority, some site's may be diluted and have lots of PR on the pages, but a site purely about the topic your site is on, will pass more authority on the topic that your site is about.
Google has even said that the best links are relevant to your own, and the people who have I seen hit by Panda, Penguin are always because they have 100's or 1,000s of irrelevant links.