There is not much material difference. They both recirculate water. I have had both along with Korallin, Knopp, ASD, AquaMaxx, Tunze, MRC and a few others. They all are more alike than different.
I tend to like reverse flow the best and also reactors that trap excess co2 in the top. I am NOT a believer in using a pH monitor or probe, so I like the reactor to physically tell me if there is too much co2. Korallin does this better than anybody.
You can tune any of them to work flawlessly... you can also screw up the operation of any of them.