For now Cav is ahead, he has WC gold + silver, MSR, 30 Tour stages (2nd all-time, 4 shy of freaking Eddy Merckx!), 15 Giro stages, 3 Vuelta stages. He's 3rd all-time in GT stages. He also has nearly 150 victories on the road, 60 of them WT level. He has points jersey's in all 3 GT's. Not really much sprinter could do...
Sagan on the other hand is way more exciting rider, and versatile. His wins are much more memorable, and I think it's just a matter of time when he's going to surpass Cav. Cav is among the very best sprinters of all-time, maybe even the best, but Sagan is on the way to enter the pantheon of cycling Gods.
So for me still Cav, but just a matter of time...