Both will do the job but my preference is Pinky. I switched out my 4 HOBs and canister filter. I find it easier to cut to shape to fit the filter basket. It keeps its shape so its easier to rinse out and reuse.
Pinky’s is made by small family owned business in my hometown so I feel better about supporting them than buying Poly-fil at Walmart.
Polyfil is available in loose fluff and in batting.
I started using Polyfil and used the loose fluff.
My new bag I got the batting and like it better.
It is not as rigid as something as Pink Filter.
Both are fine mechanical filtration, but different.
If you have room to put down a couple of layers, I think the Polyfil batting is better.
If you only have room for one layer, then the Pinky Filter is probably better.
I not used the Pinky, but have used these from Amazon......
$14. This is advertised as 1" thick, but more like 1/2" thick. I have tried re-using it by thoroughly rinsing it out and even doing a mild bleach soak and then soaked in de-chlorinator. It shrinks down to 1/4" thick and while it works, it is not fluffed up any more.
filter pad $17. They have a ton of good reviews with pics on Amazon. This one costs more per foot than the Aqua-Flo, but it is thicker, and it feels more dense when you rub it between your fingers. Also, it seems to be re-usable at least once if not more without shrinking down to 1/4" thick like the Aqua-Flo. I think the Aquatic Experts brand is a more quality pad than the Aqua-Flo, but you pay more.
In my 1 canister and my Aquaclear's, I actually put down layers of Polyfil and top it off with a pad I cut from one of the rolls I mentioned above.