Working with Stripe hasn't been error free. I've had one or two nasty bugs. But the product is fluid, works, and most importantly, they have great customer support. I wouldn't mind paying a little extra for it.
I'm a relatively small fish, but they replied within hours and fixed the issue. On a Saturday. As long this "Saturday test" remains true, I'm a happy user.
Haven't looked into the alternatives, but I hope I can move most commerce over to Bitcoin since I can run that fairly cheap internally to the company (and bypass PCI compliance, etc)
EDIT: Maybe I was being overly critical in the first half, but in general implementation has been a bumpy experience. Most transactions on this platform are microtransactions, so it isn't that Stripe is expensive as much as I'm using it in an unconventional way, and not having a $0.30 static fee drastically changes my profit margins