Pharo vs Rebol

In Pharo everything is an object. Compiler - object, network - object, method - also an object. And objects communicate with messages. No operators, no control-flow statements. Just objects and messages. Few things to learn, but you can learn OOP well.

There is good, free documentation including several books written by experts with extensive examples. There is an online MOOC. There are many tutorial videos. Supportive conferences and community. Even a professional support option if desired.

The nature of Pharo being a "live" environment allows you to perform live updates to your system without requiring to restart it. You can upgrade/modify classes while serving requests at the same time.

The framework for developing sophisticated web applications in Smalltalk is developed in Pharo. Seaside lets you build highly interactive web applications quickly, reusably and maintainably.

No need to search google for compact beautiful examples of how to do things, your live environment source is available and you can easily live search, see how it works and copy how the masters would do it (examples most languages still copy too).

Most languages are still copying the Smalltalk tools of yesterday - GTInspector (written in Glamorous) takes live exploration of code/running objects to a new level. It's really slick, and better yet, you can easily write your own inspectors in 10 lines of code.

Use 32 bit or 64 bit versions of Pharo on Windows, Mac & Linux.

MOOSE environment provides extensive, easily leveraged and class leading tools for code analysis and improvement.

Roassal and Mondrian provide fantastic and easily used frameworks for graphics, graphing and advanced visualisations (comparable to D3.js) but with much less code. Visualisations can be rendered into web friendly graphics (SVG, .png etc.) without additional work.

Rebol's name came from "Relative Expression Based Object Language". Rebol is a functional language and everything is an expression that returns a value. Things that have to be baked into the grammar in other languages are simple function calls with block arguments in Rebol.

Code is data, and data can be code. Rebol is based on a simple block data structure, used both for data and for the code itself. Blocks can be manipulated programmatically, and then evaluated as code. This makes metaprogramming easy in Rebol.

Almost natural language, for example: write %out.html read http://google.com.

Beginners are usually stuck making command-line applications in other languages, because GUIs are too hard. Rebol GUIs are easy enough to start with.

Rebol's simple homoiconic syntax makes it easy to create "Rebol dialects"--domain-specific languages optimized for a particular purpose. The Rebol distribution includes many of these, and users are free to create more. These DSLs make tasks that would be complicated to express in other languages easy.