The ink makers(OEM) sue anyone that tries to sell the exact same formula ink as they do. So, in that regard OEM's provide the best solution to thier product but they always mention thier paper(media) as well for absolute best output. Compatible inks do fine though, but for achieval output or photo, that maybe a constant open question as those ink suppliers vary. Warranty issues, I won't go there. For practical purposes compatible or non-OEM inks do fine as long as you trust the vendor. But, if you want the best operation for your printer, OEM ink is the expensive way to go but very possible the least problem prone to ink issues. But, guess what I fixed alot of printers and I strongly recommend do not buy an "EPSON", its really has ink related problems as the printhead isn't replaced like the others when it becomes low. You can easily fix bad print quality when you replace the printhead(ink cartridge).
good luck -----Willy