I am in the process of migrating all of my analyses from Matlab and R to Python. I have been meaning to do this for quite some time and finally pandas is mature enough to be able to completely replace both Matlab and R for straightforward tasks. If I need something Python doesn't offer, it's still fairly simple to do isolated tasks elsewhere. For me the biggest reasons for change are easy integration with the web and better language features (for Matlab, R language is great, just terribly slow for intensive tasks).
What I miss the most:
- Matlab <--> Excel link (on Windows) - an excel add-on that lets you send back and forth arrays very easily. You need a spreadsheet when you work with datasets, and interchanging data through files just isn't that convenient.
- Matlab's IDE features (debugging, documentation, publishing, variable inspection).