If you want to get started as fast as possible with computational Bayesian inference and don't need the performance and advanced features Stan, I'd recommend emcee [2] which is a lightweight python MCMC sampler.
Final recommendation to the HN crowd: Bayesian Data Analysis 3rd Edition [3] should be on your desk if you are thinking about using any of this software.
[1] http://research.microsoft.com/en-us/um/cambridge/projects/in...]
[2] http://dan.iel.fm/emcee/current/
[3] https://www.crcpress.com/Bayesian-Data-Analysis-Third-Editio...