Has anyone here tried this alternative peer review platform 'Peerage of Science'?

Peerage of Science received 102 submissions in 2017. Some submissions get zero reviews, but those that are reviewed have a decent chance of getting publishing offers from participating journals: 60% received at least one publishing offer, some got 4 or 5 offers. The other submissions - probably - got negative reviews and then of course do not attract journals either.

But as an author your options are not limited to participating journals; you can always choose to decline offers, and also "export" the review to any journal of your choice (= create a link that you can give to any editor of any journal, giving them access to this one process reviews in Peerage of Science). It is then of course up to the receiving editor if and how they want to use those reviews, but Peerage of Science makes them available and trustable (it's not a PDF author gives them, but password-protected link to content on peerageofscience.org website that author can not modify).

So give it a try! I can't promise your work will get reviews, and certainly shall not promise you will get positive reviews - Peerage of Science is about doing peer review rigorously and well, not quick and easy. But there's little you can lose, as it is free, you get to stay anonymous as author, and you define the deadlines.

Full disclosure: I am the founder of Peerage of Science.

I have submitted some mathematics articles for review there. The website was poorly made for this purpose (one needed to submit an editable file, rather than a PDF, and there was no integration with Arxiv such as a possibility to simply submit an arxiv link) and I got no reviews. A biologist would likely have a better chance and experience.