I'm not quite sure what it is about the gun. I like to use Spinning Up on it because if you can control it right, it just shreds enemies. Normally the gun without the catalyst recoils a predictable left. Sometimes having that kind of recoil is good. It helps you fight strafing targets on occasion. But with the catalyst done, it feels like I just slapped a Counterbalance Stock mod on it and I sometimes have trouble sticking my aim on targets when a full-auto gun recoils straight up. Depends on the gun though. I appreciate the healing benefits, but I feel like now the gun is a little bit harder to use, I guess? I use auto rifles all of the time and I'm a big fan of them. Maybe I just have to let it grow on me a bit more. I was using it non-stop trying to get the catalyst done, so I'm probably too adjusted to how I was using it. I was getting some nice multi-kill final blows too. The catalyst feels really good in PvE though. I definitely dig it there. This is just the first impression of the catalyst to me. I may update this post with my successes using it.