I want to post my manuscript to bioRxiv before submitting to formal journals. I have several concerns:
In fields that use arXiv, publication in arXiv does establish a definitive date-stamp on the work (and an accompanying archival DOI) that is generally understood and respected by practitioners in the field. Nobody could reasonable "scoop" a work published there without being called on it by their peers.
bioRxiv is intended to provide the same for biology-related fields and technically does so. The culture of those fields, however, is often not yet as accepting of the idea of pre-publication and incrementally evolving works. Hence, for example, the much greater concern with the ideas of "priority" and "scoop" to begin with. A few journals still even consider sharing a pre-print in bioRxiv to be a sort of "self-scoop" that prevents you from submitting for peer review in that journal!
Still, the only way to change this culture is to embrace more open and sharing practices. I would advise checking whether others in your sub-field use bioRxiv, checking the publication policy of your target journal in SHERPA/RoMEO, and checking if your co-authors are amenable to pre-print sharing. If you see others in your subfield sharing, and if there is no veto from the journal or co-authors, then go ahead!
(1) I discussed this question recently with few colleagues from biomedical field, and, as far as I can see, major part of the field do not accept a non-reviewed experimental findings as a proof of discovery. This is mostly for two reasons: first, there is no single preprint server in biology. There are BioRxiv, F1000, PeerJ, ASAPbio, Arxiv q-bio, and probably more. And all these papers are not indexed in the main paper bases, like PubMed or WoS. So to keep up with the "pre-publications" one will need to check every single pre-print server. And this is too much. Second problem is the fear that if the field will start to acknowledge the priority based on the claim, without checking the rigor of experimental design, it may promote the sloppy data handling, because researchers will rush to put their flag everywhere. And we are talking about the very populated field, where many sub-fields have a clinical relevance or otherwise related to highly sensitive problems of human/animal health and well-being.
(2) Probably no, but this is the risk that one takes in research when he/she is going to conference, submitting grant application, and etc. The question is whether this risk provides some benefits in return.
(3) I still think that biomedical field, in general, would benefit from fast communications of the research finding behind the closed doors (i.e. without making scientific statements to the public). Even from the personal perspective, it is a way to faster position yourself as a researcher among other colleagues.
Putting immature article before peer review is not proof of discovery. If yes, we can easily scoop other's findings by posting quick, short and sloppy article in Preprint server (after knowing their data for example in some research conference) .
Also, the benefit of Preprint server is that researcher can publish there data quickly before long peer review and publication process. However, in reality, most of the author post their articles in preprint sever when they noticed that some other group were also working on the same topics and wanted to insist their priority. This is quite ugly and selfish motivation.
All paper needs to go through peer review when the paper needs to be polished. Even though that is time-consuming, this process is equally required for all academic paper. Therefore, posting article in preprint server after knowing some competition is dirty scooping.
