I looked some at some reviews and don't want to share my thoughts after reading some since we might have different conclusions. All I can say is, they are regulated.
But you know, why Gemini? There are other more exchange. What features of them did you see that's why you become interested?
From analysis I got from several sites and feedback, I feel Gemini is quite good in service. Maybe this site will be a coinbase rival in future, at least we can give trust to this site to develop. Moreover, this company was founded in US which has pretty strict regulations for every new company.