I run two sets. The Bullfrog ones that came with my spa, and a set of Guardian Filtration Products filters I got off of Amazon.
I think the Bullfrog ones are Pleatco.
There is a difference, the Bullfrog ones are more .... robust?
The don't flex as much, and the filter media may be a little thicker - maybe?
Other than that, they both work fine, they both filter my water, and they both clean up with the same amount of effort. I really do not notice a difference between the two.
I bought the Guardian ones back in January of this year, and have been swapping them monthly for the last 9 months or so. I do not see any difference in performance.
Not that I recommend using it, but the bracket for the Frog @Ease system clips into the Guardian filters too. I don't use the Frog system but I leave that bracket in there, because that bracket is a Bullfrog part, and if for some reason you throw it out and then later want it because you want to use the Frog system , it is north of $50 to get a replacement bracket.