Having worked as researcher/dev in both private office and open space setup, I am absolutely convinced that private offices are way more productive than open office setup for researchers and developers. Most, if not all, of my colleagues feel the same. In fact, I don't think I will ever accept an offer from a mature company (not startup) which houses its developers in open space.
For me, open office + headphones = private office. At a vastly reduced cost. I know that doesn't work for everyone though.
As far as noise goes, even with audio engineers on staff, the level of disruptive noise was horrible. People having calls at their desks, testing mobile notifications, etc. Thankfully, I worked at home 50+% of the time as getting productive work done in the office was incredibly difficult. Large open space + open office = bad idea.
Our office in Stockholm, while an open office, had many smaller sections offset by walls, break rooms, etc. It was a much better experience overall, but still not optimal.