...I've heard of people having issues with the slotted rotors. Never tried them...
Different application, I've had drilled/slotted rotors. For the daily driver I wouldn't recommend them. And, generally, you will not find them on a certain track applications either, because they're prone to cracking over time.
I had two experiences, for what they're worth. First, the only place I could honestly claim I noticed any difference was driving in the rain. In heavy rain and highway speeds, you will definitely notice braking begins a shade quicker as water is more quickly displaced. Its like bad shocks. You don't notice it day-to-day with standard slabs. But you definitely take note in rain with the drill and slots. That alone, not worth the expense in my opinion (and that's all it is).
Second, as the miles accumulate, the holes, and slots in particular, will fill up with brake dust and other material. Pulling them and hitting them with a wire wheel once in 10K miles would be advisable. Not worth the headache. Again, imo.
They look cool--and that's a fine justification for getting them. From a practical perspective, I'll not spend money on any more of them. It's been 5 years since I messed with them last, but I don't think things have changed that much.
2¢
