Pros
Very flexible job which can be done from home at any time that suits you and at your own path; becoming a perfect option for students, parents, etc. Several jobs available if your field of expertise is business or medical health.
Cons
I have applied for freelance engineering writer and I have specified to them my particular fields of expertise. However, all I received from them were jobs related to sectors that were not even closed to what I have specified so I guess they do not have any person or team dedicated to this matter. Also, even though I was told they manage payments twice per month I was meant to receive my first payment one month and half after the submission deadline and I am currently still waiting for it; so this position would work better for people who do not need or depend from this money as their regular salary it is more an extra source of money but not very reliable.
Also, they are quite rude in their treat to their writers. Once I asked about a fee they have charged me and they do not try to explain it to me; they just answered me rude emails saying that it was all explained in my contract which, by the way, I have never received nor signed. I also received a very rude answer with a threat of closing my account included, so in general a very poor treat to writers and not very caring about their employees (at least for the writers, I cannot say anything about how is working at the Company Headquarters).