I currently work at home 3-4 days a week with the others being in the office, usually for meetings and collaborating on things.

The office is an open floor plan with very poor noise reduction. When not in meetings in that environment, it is hard to get work done even with headphones. Visual and audio distractions persist. That said, there are times where getting together is helpful.

When contacted by companies, I ask about telecommuting. Many play the "it is up to you and your manager once you are established" game. Result - thanks but no thanks.

Time spent in the car/traffic is productivity lost.