Retail e-commerce has outperformed brick-and-mortar retail during the recession, helped by its reputation for convenience and cost savings.

Data from Performics’ “2009 Online Buyer Economic Trend Study” shows nearly one-half of US online buyers felt they had found the best deals online, compared with 34% who reported doing better at retail locations.

The top three Website features that would encourage online buyers to make a purchase were themselves deals as well: free shipping, free return shipping and discounts on the homepage. Features that gave a fuller picture of products, such as customer reviews and interactive information, were less persuasive.

Among younger adults, however, those features were much more important. Eight in 10 respondents ages 18 to 24 said they were more likely to purchase from a site with consumer reviews, and the same number would be swayed by interactive information.

Respondents said they found the best online deals at retail company Websites and search engines, followed by comparison shopping sites. Just 4% found the most savings at Facebook, and 3% at Twitter.