Compared to the rest of the DFW Metroplex market, the Allen submarket has more expensive rates, and you'll have to negotiate above asking rent to be in this hot region.
In the last 90 days, 19 listings have been posted online, which means listings most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 95% of the office spaces in the Allen are subleases, so you might be able to sign a shorter term by taking over a previous lease. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 2,630 sqft, there are still 0 new availabilities below 2,000 sqft. Most buildings in this market are around 2 stories. Most buildings in this region were built in 2005 and are Class B.