Internship with a start-up vs Co-op with a Research Institute

I have two job offers that I'm seriously considering and I'd love some feedback on what to do. I have an offer for a co-op position with my university's research institute paying $25/hour, which is pretty damn good for an area with mid-range COL. At my school, the co-op program means that you intern with a company for three semesters, alternating with school (in my case, Summer 2017, Spring 2018, Fall 2018). The pay also goes up with each semester. I'm heavily considering doing grad school because I'm interested in doing R&D stuff long term, so I think working here might be good for that. The name carries a decent amount of weight from what I can tell, it's not JPL but it's respectable and recognizable. I'd be working on some RF engineering stuff and software-based DSP, which is a little more hardware-y than I want but it's interesting enough for me (they did specifically say I'd be doing the software side of things). I'd also get to do some data analytics with machine learning, which is right up my alley.

On the other hand, I got an offer from a start-up in the same area that's working on making an autonomous car. The catch: I'd only be making 17/hour. This would be an internship, so I'm only locked in for the summer. I think autonomous cars are the shit, and I know I'd be able to have an active role and get a ton of experience. The start-up is pretty small and they're in the relatively early stages of design. If it's anything, I have a friend that works there and he says he loves it.

So, for me, the choice is about 50/50. I could work on something really cool and only be locked into a commitment for one semester, but have way less money to pay off college debt and not have quite as recognizable of a name for future jobs/grad school. Or, I could get 3 semesters of solid experience at a fairly respected research institute, take out a much larger chunk of my student loan debt, and be pretty set up for grad school, but have to be locked in for a year and a half and not get to work on an autonomous car. There's also some added opportunity cost for the co-op in that it'll take me one more semester to graduate (though I'll still only pay for 8 semesters of enrollment) and I'll lose the opportunity to try for a Big-4 or similar level internship next year.

Thanks for any help.