Pharo is the most actively developed and used Smalltalk environment. There’s plenty of evangelism and information on the Web about it in a similar way to Lisp. Pharo takes the “integrated” in IDE to a whole new level, which is one of its selling points. You can find plenty more information about how Smalltalk-style OOP is superior to Java-style OOP, so I won’t rehash that here.
One of the key words in that statement was "actively developed". Cincom, Instantiations, and GemTalk have some great people working on them, but Pharo7 had 75 different people contributing - including probably almost as many full-time people as the commercial developers (maybe more).
I love Pharo, so don't take this as me trying to take anything away. Cincom "actively develops" VW as well. I keep in touch with that side just for my own information. Pharo is doing a phenomenal job.