Just like the title implies, whats the best lifter for a cam? Are there any advantages to one over the other, what one will last longer?

 

Any given cam is designed for one or the other- they're a matched set. You can't just change lifter types without changing the cam.

Roller cams offer advantages of higher lift and higher valve acceleration rates than you can get with a flat tappet- that typically equates to more power potential, apples to apples. However, there are offsets to this- cost being one (flat tappets are dirt cheap) and setting up a roller valvetrain to work in the higher RPMs is not always a "throw parts together and turn the key" type of affair.

Roller cams are also easy to break-in on first install (wiping out lobes is rare), where flat tappets require a specific break-in regimen if you want to have your best shot at letting the new cam/lifter live a long and healthy life.

Better? What fits your needs and budget best is what's better. Both have their place.