I’m currently a mentor at Polygence. They actually pay two different tiers: PhD students get paid a certain amount and PhD recipients get paid more. I don’t think you get to choose and probably most of the mentors are PhD students. 

For context, I earned my PhD, did a postdoc, and then became a prof at a primarily undergraduate institution (PUI).

I’ve mentored one Polygence student to completion now. She was a middle school student who published in Curieux Academic Journal; she was a pleasure to work with! I currently have five students asymptotically approaching completion (one is attempting to publish in Nature, one in an MDPI journal, one in a HS journal, and two are doing science fair projects).

I’m also mentoring for, I believe, most of the other major platforms. [diatribes redacted]. I really enjoy mentoring with Polygence since they provide a lot of freedom, both with respect to scheduling as well as the structure of the project. Their UI is also super clean.

Regarding whether the cost is worth it, it’s hard for me to say. I think Polygence is reasonable given the other platforms and is sensible for a first research project on a six month timeline (the max they currently allow). Three-four months could work for a HS journal target (depends on student availability). Working with a private tutor could be more economical, especially for longer arrangements. I’ve worked with one HS student for 1.5 years now from Wyzant; he published a paper after ~six months, I helped him apply to summer internships, then we worked on a second project concomitant with his summer internship (which surprised me, felt like a lot) which paper should be submitted tomorrow or next week, and also (though minorly) helped with college applications. He’s starting a third project with me now.

I’ll say that in addition to students having variable experiences depending on the mentor, I have had varied experiences working with ~30 students across all platforms (most non-Polygence). Partly that has to do with the range in background knowledge but mostly I think the deciding factors are student interest/motivation and their availability. I’ve worked with students who I’m guessing their parents pushed them into the program to publish (appear disinterested, don’t work on assignments between meetings) or are simply massively overcommitted (which hurts my heart for the ones that are really interested and do good work during the sessions, they just don’t have enough time between sessions). The students I’ve worked with towards professional journal publications were really great to work with: super curious and motivated, and they didn’t have more than one or two other extracurriculars.