From the configuration point of view, the improvement of Pro GPU is the most obvious.

The peak power consumption of Pro is 3 10W, which is nearly twice that of PS4.

Slim is thin and light, and the PS4 Pro is much heavier.

Detailed comparison between pro and slim:

In terms of appearance, the PS4 Slim is not much different from the current PS4, but the size is a little smaller. Generally speaking, it is similar to the first edition of PS4. In sharp contrast to the thinness of the PS4 Slim, the PS4 Pro is much heavier, and the whole three-layer fuselage looks like a sandwich.

In terms of performance, PS4 Slim is exactly the same as PS4, both are 1.84TFlops, while PS4 Pro adopts the latest AMD Polaris architecture GPU, which greatly improves the performance compared with PS4 Slim, reaching 4.2TFlops, and also supports running games with 4K resolution.

If you use a 4K TV, or want to start with PS VR, maybe the PS4 Pro is more suitable. If you just try console games, then PS4 Slim is a good choice.

On the left is PS4 Slim, and on the right is PS4 Pro.