I would go with the basement. It is the easiest to maintain as far as environment goes. Just make sure you have a fresh air supply. I also grow in the open, although I find that their is usually less useable light due to the fact of none reflective material.

Remember atticks are the hottest part of the house in the summer and the coldest part in the winter. These dramatic temp swings througout the year tend to make dialing the environment in tricky every 3 to 4 months. Just a thought.