Last night I completed my first Feindish level Su Douko puzzle. It was number 182 from The Times. You can read and find lots of puzzles over at The Times. I guess this one puzzle took about 2 or 3 hours althogether.
Updated I've been complting The Times Feindish level puzzles in 30 to 40 minutes now. No. 279 seemed very easy to be honest, although the writers of these puzzles say there is no scientific answer to a particular puzzles difficulty.