oem are your best bet, they run at about 30-40 each at any auto store (autozone, pepboys, etc.).
If it's some random brand that you have never heard of you should probably be concerned. Most cheap slotted rotors from eBay are crap. You can get slotted rotors just get them from a reliable brand. Same thing with pads.I need to replace soon my front pads and I think the rotors. I am looking at ebay slotted rotors and ceramic pads.
Anything I should be concerned about with this setup, or should I just stick with OEM non-slotted or cross-drilled rotors?