Beyond Hell Mode - Is it worth it?

I noticed that Tier 15 is the highest tier for items. Tier 15 can be obtained in stage 9 and 10 of hell mode. So, what is the benefit of going Inferno and Dark mode? Better stone drops? More experience? More gold? Higher change of Unique's?

 

Nothing new I guess. Just more challenge

That's why

Luckily, I drew Inferno sword while I was in nightmare... (:

Its worth it

where you get more stone drops?

Ussualy from playing / u get message with free stones or from time to time i buy them with 60-120 souls after u finish a round

U buy them *