The biggest con is just the flip side to the amazing benefits of remote work. Since you don't spend time in office with your coworkers, you have to figure out ways to make opportunities to connect and collaborate. That requires extra thought and effort that comes for free in an in-office environment.
But in my opinion, this is negligible when compared with the benefits and flexibility that remote work offers. The other con that I would express would be that Rebuy is right at that difficult space of figuring out how to function at a slightly larger scale than startup while still having the spirit of a startup, which makes administrative systems still feel a bit home-brewed.
And sometimes workflows depend a lot on tribal knowledge rather than being clear, well-documented, and accessible to anybody who needs them.
All that being said, I have not had any extreme negative experiences at Rebuy. Have loved my time thus far.