Great to see Pharo on HN. I picked Pharo and Glamor [1] for a new IDE that I'm working on [2] and it's a real pleasure to work with so far. I didn't find anything else in the same league.
I'm not sure how "official" this answer is but to me Glamor is a set of extensible ("moldable") development tools that are included in the Pharo distribution: Spotter (object search with better UI than google), Inspector (click through object graphs with domain-specific visualizations), and a few others like the debugger.
So when I say that I picked Glamor I mean that my plan is to extend the Spotter and the Inspector to be able to navigate and visualize the internal data structures inside my application.
I also would like know this. I find the Pharo ecosystem challenging to understate as the documentations aren't as rich as other platforms with more volunteers. Or maybe it's because of the more exploratory programming/learning style of SmallTalk and it'd just be easier if I just poked around the image to learn rather than reading the docs?
[1] http://gtoolkit.org [2] https://github.com/studio/studio