If you could, at the same time, clean up the taxis so that they're not disgusting then potentially yes. But the difference between an Uber vehicle and the standard taxi in NYC is so alarming that I think Arro is actually solving the wrong problem.
You'll want to know percentage of company, and if they've got a valuation of the company already what that value is. Unlikely if they're "fairly early" that they know their valuation, so ask them for their projected valuation at the key stages. If they're offering equity, that's lovely. But that means that they have to pull back the curtain a little bit so you know what it all means.
Jeans and a collared shirt. If it's a senior position throw a coat over it if it looks right, but don't throw the wrong coat on (yes, it's a total judgement call)