The 2.9% + 0.30 model seems to be pretty drilled into everyone's head... it's worth noting that if you get a real merchant account from a company like Chase Paymentech or First Data... you'll get pricing as low as like 0.05% for debit cards (w/ interchange plus). All in all, it would average to around 2% or less per card you process. If you do any kind of volume - it's worth it.
That pricing is the starting tier for us. We scale with your business and make sure that we're completely price-competitive as you grow. (One of the nice things about the industry is everyone has the same backend interchange costs, so it's possible to match anyone else's rates.) As well, other processor headline rates generally don't take into account a number of other read-the-fine-print fees which can add up to quite a lot.
Said another way, pricing should actually be a non-issue in your choice of processor.
Braintree's checkout process is every bit as easy to implement as Stripe's. However, signing up for Braintree and getting approved takes longer (at least in the EU - I don't know what the situation is in the US). On the plus side, Braintree works in several countries that Stripe doesn't yet work in.
