In case anybody runs across this in the future... after evaluating Spreedly, Stripe, Braintree, Recurly, Segpay, Dwolla, and FeeFighters, I decided to go with R

In case anybody runs across this in the future... after evaluating Spreedly, Stripe, Braintree, Recurly, Segpay, Dwolla, and FeeFighters, I decided to go with Recurly + Feefighters. Recurly has a focus on recurring payments that I like and a strong emphasis on reducing failed charges that the others lacked (or didn't document well enough). Their API seems reasonable and modern, and it looks like I can scale from a "get it up right now" hosted payment page to a more-custom solution in the future. Fees look like they might be a bit high--$69/month, plus 1.25% + 10¢ per transaction, PLUS merchant account fees--but having somebody else do a good job of handling my dunning and invoicing emails well should be worth the cost. Recurly will set you up with a merchant account (or so it seems) but I'm going to augment that with a FeeFighters search. FeeFighters provides competitive bids from merchant accounts provider. They're paid by the provider, so it won't cost me anything to give them a shot and compare what they find to what Recurly offers. My second choice was Spreedly, for its abstraction over multiple services, which would give me more flexibility in the future. Unfortunately, their service came across as a bit immature and I had trouble finding webhook information I was looking for in their documentation. Also, they didn't look like they had the sophisticated dunning that Recurly offers, which was Recurly's main draw for me.