Are development environments the cat's meow?

Over the past 10 years hardware/software integrated development environments (IDEs) have improved dramatically and most now include cycle accurate simulation, automated performance tests, and power analysis. Many are built on the Eclipse platform and they are available for most every processor.

Do these IDEs save a significant amount of a design engineers development time? Do they speed time to market and make software a whole lot more reliable – just like they are supposed to? Are they the cat's meow?