I am a Rubyist that is just starting to dabble in Smalltalk and am trying to chose an implementation to experiment with. It seems like Squeak or Pharo would be a good choice, bu
The most traction right now is enjoyed by Pharo, so I'd go there. The runner-up is Visual Works. Just beware, no Smalltalk dialect is having a lot of traction right now.
My reasoning goes as follows. Today, Smalltalk is used for 2 things: Web programming and research. For both, Pharo has the upper hand (Seaside uses Pharo as its default platform, and University of Lille cranks out the most Smalltalk papers–––all built on Pharo).
The third thing Smalltalk is used for, although decreasingly so, is developing banking software. There, VW is still popular. Also, VW has the nicest object inspector.