Still have no idea how to use Eclipse after 10 years. Vim, Emacs, VS Studio, VS Code, a few proprietary ones - very easy to figure out. Eclipse seems to be a magical combination of hard to use, slow, and hated. Was there a golden period? Was it great for awhile, and now is past it's prime, like MS Word?
VA was an excellent tool for Smalltalk insofar as it allowed you to work with a big soup of classes, abstracting away source files to the point of near invisibility.
Fitting Java required a bit of shoehorning, and I must admit VAJava was an acquired taste for me. I had to sink or swim as VAJ was the official tool of my job work environment.
Having grokked VAJ, Eclipse was a godsend for me. It was similar enough that I had little learning curve, coming from VAJ; and it was a complete, professional IDE for $0. At the time Eclipse was gifted to the Java community, the alternatives were either costly or minimalistic and crude.
Eclipse continued to get noticeably better from release 1.0 to the early 3's, and I was honestly excited about each major upgrade. I would say that yes, this was Eclipse's Golden Age.