When will it stop? Productivity certainly takes a hit vs cubical/office Any recent studies backing this up? Regardless, Most hate it
From experience, Open Space is better for team communication and having a better sense of what everyone is doing (easy to overhear something and possibly commenting or get help) BUT for people (myself included) breaking concentration all the time is awful. Also, I'm one of those people who needs a whiteboard all the time and open space means less walls to place them (and those whiteboards on wheels get in the way too much, I hate going around those like a maze)
Companies are too cheap to pay for space these days.
Lots of studies. Just google it