AVOID. This joke of a company expected me to waste my weekend doing a coding challenge (with a question which was nothing to do with the role applied for) before they would grace me with their time for a real interview. This is despite my extensive open source contributions which they were welcome to review, and would probably take less of their time to review then a coding challenge.
Thoughtless people. Companies like this, who don't respect your time before you have even interviewed there, are not going to respect your time when you do work there. So just say no to these stupid take home exercises (especially when you already have a portfolio of work to back yourself up with)
Initial conversation which lead up to this was a chat with the hiring manager, who to me sounded like the usual hands off middle management technically incompetent type you find all over these hedge funds, who got in before the hiring process become totally ludicrous and unreasonable like it is today.