Its easier to build an enterprise Flex application than an Ajax application. However, you don't have to take my word for it, take the word of Bill Scott, the Ajax evangelist at Yahoo!, who told a crowd at the Ajax Experience: "In the enterprise space, I tend to recommend things like Flex because the development is much faster to get up and going".

Scott Davis, co-author of JBoss At Work and author of several mapping books, including Google Maps API and GIS for Web Developers: Adding Where to Your Web Applications, said that he was getting more interested in Flex recently, mostly because of the recent announcement that Flex would be open source.

You can read the entire article over at InfoWorld. Looks like Flex is really starting to gain momentum.