PureBasic is a great programming language for beginners and pros alike. It has a large (well-documented) library of built-in functions to do almost anything you'd need, which is supplemented by user libraries. These allow one to easily learn the language quickly and start making powerful, lightweight programs.
It's multiplatform (Windows, Linux, Mac), with most of the libraries being supported across all three. Programs can be easily written to support multiple platforms using compiler directives, without the need to use something like Java, which has its own problems.
Probably the biggest benefit is that the compiled executable are very small and efficient. The disk and memory footprint are typically negligible for most applications you will create.
Last but not least, the price of the software is extremely reasonable at $89. This is a single, lifetime license including all updates the software will ever get. Where else do you see this kind price?
The graphical interface builder that comes with the IDE leaves a lot to be desired. There are free third party GUI editing tools that work much better than PureBasic's built in one. Overall, if your software solution needs a GUI, you're better using something in the .Net environment if possible.
The other pain point is that the IDE for coding becomes a pain if your software project starts becoming very large (dozens of includes, dll libraries,etc)
Our company used this software to build lightweight monitoring tools that collect statistics on applications and servers, with almost no footprint on their performance. I don't think we would have been able to squeeze out the same performance with a comparable product in the .net or java environments.