It's harder to have conversations in an open office because they disturb non-participants. I find myself wasting time booking conference rooms when I could have simply popped into so-and-so's office.

I remember a long long time ago when the company I worked for did a big move and went from offices to cubes. I was young and naive and willing to try the experiment but within a month or two I regretted the change and things haven't gone back since.

I'd prefer sharing an office rather than an entire floor.