Just did it yesterday on the 20 def, The only really hard parts for me were the Whisperer and the final fight, since I get wrecked by the clones jutsu, ended up taking like 15 brews and a few pnecks in and did the job...

Time to do it on the 1 def next!

EDIT: Took about 12h+ blind on the 20 def, about 5 hours on the 1 def speeding through (last fight is rough! :)