What is degrees per second?

The degrees per second is a measurement used for defining angular velocity. This is not the standard unit for measuring angular velocity. It is rad/s which is a SI unit. Unit of degrees per second is $\deg/s$ or $\deg*s^{-1}$.

$$1\ \frac{deg}{s} = \frac{2\pi*\omega}{360} = \frac{2\pi*rad*s^{-1}}{360}$$

What is rotations per minute?

The rotations per minute or rotational speed is a measurement used for measuring number of revolutions or cycles a object rotate around an axis in a unit of time. This is also know as rpm (revolution per minute) or cps (cycles per minute). This is the standard SI unit for measuring angular velocity. Unit of rotations per second is $Hz$.

$$1 Hz = 2\pi\omega = 2\pi*\frac{rad}{s} = 360 \frac{deg}{s}$$

Wikipedia page for explanation on rotational speed