South Florida continues to shine when it comes to housing markets on the mend.

Palm Beach, Broward and Miami-Dade counties scored 84.7 in August on Freddie Mac's Multi-Indicator Market Index, a 14 percent increase from a year ago. The index ranks the nation's 100 largest markets by how stable they are.

It tracks home loan applications, affordability, mortgage loan delinquencies and employment. A composite score of at least 80 is considered favorable or stable. A perfect score is 100.

Home prices and sales have steadily increased for most of the past three years. In September, Broward County's median price rose 8 percent from a year ago to $290,500, while Palm Beach County's median was up 6 percent to $285,000, local Realtor boards said.

But the more the market improves, the harder it seems for Linda Casadei to find a home.

Casadei, her husband, Roberto, and their two daughters have been looking for homes in Parkland and Boca Raton since they moved to South Florida in January.

The Casadeis say they're deliberate and thorough, but they never expected to still be in the market nearly 11 months later.

"When you get around to seeing a house, you have a good feeling about it and you like the neighborhood, it always has a contract on it or it has another offer," Casadei said. "You've just got to let it go and keep searching."

A shortage of homes for sale leaves prospective buyers scrambling to find a place. The number of homes for sale is down from a year ago in both counties as a recent sales surge has depleted listings. Some sellers are asking too much, and most buyers refuse to overpay, real estate agents say.

Still, in this market, sellers who make even modest improvements find that buyers' interest soars, leading to bidding wars and higher profits, agents say.

South Florida agent Judy Trudel said one of her recent clients ripped out old carpeting and added stainless steel appliances to his four-bedroom Pompano Beach home. It drew three offers and sold for $325,000 — roughly $60,000 more than if he had sold it as is, Trudel said.

"When a property is clean and it looks good, the buyers can see themselves living there," Trudel said. "A little bit goes a long way."

In Lake Clarke Shores, near West Palm Beach, agent Randy Bianchi said his seller was a master gardener who kept the front landscaping in perfect condition. The two-bedroom home had no clutter and wooden floors that shined. It sold in five days for $260,000, a few thousand dollars over asking price, Bianchi said.

"Even the owner was shocked," he said. "She got it ready to market, and it made the world of difference."

Just less than half of the 100 metros are considered stable, according to the Freddie Mac index. South Florida ranks 35th, an improvement of 24 spots from a year earlier.

The tri-county region reached the 80 threshold in May for the first time since August 2008.

Fresno, Calif., is the top-rated market with a 99.4 score. Austin, Texas, is second at 96.6.

Len Kiefer, deputy chief economist for Freddie Mac, said South Florida's index score is increasing largely on the strength of fewer delinquent mortgages.

Interest rates remain low — around 4 percent — and that's helping to keep costs down for buyers. But affordability is a concern, particularly because salaries aren't keeping pace with home prices, Kiefer said.

"We've got to get some wage growth to offset the fact that prices are rising," Kiefer said. "The middle class, or someone making the median household income, is finding it very tough to afford homes in the [South Florida] metro."

Much of the new construction in the area targets wealthy foreign buyers, though slumping economies worldwide could curtail demand for luxury homes, analysts say.

"That would be good news for domestic buyers because it would reduce competition," Kiefer said.