Denominus: Playing through Insane has got nothing to do with achievements, bragging rights or anything like that.
It has everything to do with how you play in response to this extremely harsh FORCED penalty hanging over you. My entire playstyle changed moving to Insane difficulty, its the same game but a vastly different experience. You use EVERY tool at your disposal and you do your best to be over prepared for everything. Going into a tough fight is nerve wrecking as is scraping through a fight on 5 hp.
IMO, the best TW2 experience is found in Insane difficulty, just as long as you don't die =)
This.
My gameplay is completely different going through on insane... I potion up every trip I take into the forest, I move slowly, examing my surroundings carefully... it makes me feel much more like a real witcher.