Developed for internal by PowerFlasher, the FDT (Flash Development Tool) wowed freelancers so much that the company decided to launch it as a commercial product. Like Flex Builder, FDT is built upon the Eclipse framework and therefore has many similarities with other Eclipse-based tools, not least JDT upon which it is based.
It is great to see competing tools out there on the market and it can only serve to strengthen the popularity of the technology.
PowerFlasher’s tool can be found at http://fdt.powerflasher.com. It is really worth a look.