Top 33 Free Data Mining Software – with a brief description of each. My personal take: RapidMiner has the fastest (a few hours) learning curve, it is the best for fast learning and applying various ML algorithms, without going into much details; R has a clear logic and a pleasure to work with, although it is harder to learn, especially for non-programmers, but if you want to really be flexible in R you have to master programming in it, and it cannot be done for a couple of weeks. I struggled with Rattle GUI for R, and gave up without any luck running it on my Mac.
Top 30 Software (a third is free) for Text Mining – both RapidMiner and R have free modules for text analysis. STATISTICA has a module for text analysis; while it is not free (and expensive) but solidly done software — I used it a lot in the past and liked it.