I'll just answer briefly, as I'm sure others will fill in more details than I have off the top of my head.
Yes, Kickstarter changed their payment processor from Amazon to Stripe some time ago. I suppose this makes it easier for those unfamiliar with Amazon payments.
The USPCC vs EPCC/LPCC debate is still ongoing and in constant flux (both in terms of pro's and con's, and general opinion). The USPCC still has the superior finish in terms of glide. EPCC/LPCC used to have a quicker turnaround, but with the increased demand they're now becoming quite backed up. They also have always had a 1,000 deck minimum, and although the USPCC has started toying with the idea I don't think that's available for everyone yet (currently at 2,500 decks). EPCC/LPCC has had better registration up until now, and the USPCC runs usually end at the upper limit of the 10% over/under (which the designer/producer then has to pay for), something that I have not heard that much of from customers of EPCC/LPCC.