Payment always One Time, but this site shaving too much views:
My daily stats:
Safelink**: 7800 - 8600 Views / Day
Shr**k: 7900 - 8700 Views / Day
Ouo.io: 5100 - 5600 Views / Day
Rates is good, but final earning is not better than other. you can generate same revenue or maybe (MUCH MORE) with other shortener url.
So, what the conclusion ? I'am sure this is just a marketing trick. They give you better rates but they shaving more than 20% your account views.