The typical asking rate per listing is in the $30's per square foot per year. The Mission Viejo submarket is going through a decline in rates. In the last 3 months, the median rate decreased $2 per sqft per year. That's a 6% decrease in rent.
Compared to the rest of the Metropolitan Los Angeles market, the Mission Viejo region has greater rates, and you'll need to pay a premium to be in this hot region.
In the last 90 days, 12 listings have come on the market, which means listings most likley are going fast. 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.
The standard measurement for office space in this area is around 1,980 sqft. Most properties in this area are close to 2 stories. Most buildings in this area were built in 1988 and are Class A.