I don't have opinions, I have facts that I have purchased through lots of work, expense, and testing. I sponsored a few track cars to pay for that knowledge. I also sponsor a few street rigs to get input from other areas. We tested slotted against smooth face for several races, actually a whole season. For anyone who is not in a race environment what we learned is a high quality slotted rotor works enough better that you can actually say they work better and not be lying. The problem is where that improvement lies. They will shorten stopping distances at the end of a very high energy event where you are on the brakes hard. The trade-off is they have a non- linear response in that they work a fair bit worse at the beginning of the event to a bit more than halfway through it and then the response ramps up in a very steep curve which is also difficult to modulate to prevent lock up.Those are only your opinions... I believe they are better and have never had any issues with them in any car I've put them on.
For the average user who is not driving like a maniac most of the time, that equates to a worse performing set up since you wind up using them in the range where they perform the worst. That and we don't do drilled since we have found that it is rare that they don't cause cracks when the rotors are used enthusiastically.
Work better is far too subjective.This is only the third Jeep I've used them and installed them on dozens of cars. In my opinion, they simple work better.
I still see them used on many performance cars out there also and until I find and see proof otherwise, I will continue to recommend them.