Most listings are in the $30's per square foot per year. The Darien submarket is going through a decrease in rates. In the last 3 months, the median rate decreased $3 per sqft per year. That's a 6% decrease in rent.
Compared to the rest of the Fairfield market, the Darien region has higher rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 8 listings have been made available, which means spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. There aren't many listings below 2,000 square feet posted, so finding a space for a small business might be tough.
Even though the median size is 3,220 sqft, there are still 0 listings below 2,000 sqft. Most buildings in this region are around 2 stories. Most buildings in this area were built in 1980 and are Class A.