[claudius]

The arXiv is not necessarily a tool where everybody can publish everything. It is primarily a tool for the community, which consists mostly of people with affiliations. If you want feedback for something as an outsider, go to conferences and present a poster.

[tagrun]

A few more nice points about arxiv: 1) peer-review can take sometime, it's nice to be able to get your work out earlier publicly for the records, which you can make a claim later on 2) even after publication, it is accessible by anyone (and it is common to update the arxiv version to match the published version, including improvements after peer review)

It's probably not very useful for getting comments. The only comments I ever get are along the lines "I see your nice manuscript, please don't forget to cite these papers of mine". To my surprise, it is mostly "leading" physicists who send such mails (which makes me doubt their citation records).