So what is Genstat?
GenStat is a comprehensive statistics system which offers ease-of-use for the novice user through a Windows menu interface, or power and flexibility for the more experienced user through a powerful command language interface.
It is developed by VSN intl
VSN International Ltd (VSNi) is a data analysis and statistical software development company, providing comprehensive statistical and data analysis to a variety of different market.
So it basically not a free software.
Then what is PSPP?
GNU PSPP is a program for statistical analysis of sampled data. It is a Free replacement for the proprietary program SPSS, and appears very similar to it with a few exceptions…. PSPP can perform descriptive statistics, T-tests, anova, linear and logistic regression, cluster analysis, factor analysis, non-parametric tests and more. Its backend is designed to perform its analyses as fast as possible, regardless of the size of the input data. You can use PSPP with its graphical interface or the more traditional syntax commands.
So it is a free software, that runs on cross platforms: Linux, Mac, and obviously Windows :-).
Then how to install it on Mac?
There are many sources that make explanations on how to do it, but I find that this link should answer the question (https://bmi.cchmc.org/resources/software/pspp).
Now is it good? The answer is always depend on the situation and what kind problem that you need to answer. But you can get some reviews on these links:
It's your call to choose. But if you're a student that want to work at home with no network access to lab, and have a Mac or Linux machine, then you should try it or just stick with R for a while like I do.