Braintree has a very high monthly fee (200 a month min) and so does not seem good for startups (they seem to forget about the fact that startups grow).

I tried to negotiate with them... They came down to 100 min which was still more than double my other options. At this point when I said it was higher than I was comfortable with, the sales rep started asked me "what would you propose?"

I wasn't sure how to answer that, but when I finally answered "how about matching or nearly matching the minimum given by x" (which was around 40 a month minimum) and I'll sign up today. At that point, the salesperson sent me a miffed-sounding response saying they can't go below the 100 a month minimum (why ask what I propose, then?) and walked away from the negotiation. YMMV.

edit: checked my emails with them and edited for accuracy