120k base as a full-time employee vs 150k base as an ETW (contract-to-hire)

I have an offer from Nike for 150k base, but it's as an "ETW". I have read a lot of warning posts about how ETW's can be let go at any time, how they are treated as second-class citizens, how the conversion rate from ETW to full-time is deceptively low, etc. I'm sure a lot of these posts are sensationalized, but the question is by how much. Meanwhile I have an offer for 120k base plus stock options (already tried to negotiate higher base) from a unicorn startup, who by all accounts have a stellar company culture, great benefits etc. It's full time and I wouldn't have to be worried about job security (at least, not in the same way. You know what I mean). The whole contract-to-hire thing has always sketched me out a bit. I wouldn't technically even be working for Nike, I'd be working for the consulting firm that put me in touch with them. The whole thing just doesn't feel all that secure compared to a normal full-time position. But maybe I'm just being paranoid, and the obvious answer is to go for the better paying job. Anyone with ETW experience who can weigh in? What are some other differences between full-time and ETW that might not be so obvious?