
Using a familiar programming language leads to significant productivity increases over an unfamiliar language.

Using a high-level programming language leads to huge (many factor) productivity increases over low level languages, both in terms of development speed and lines of code (table copied from "Code Complete 2", by Steve McConnell).

Language	Program size compared to C
--------	--------------------------
C		1.00
Fortran 95	0.50
C++		0.40
Visual Basic	0.22
Java		0.17
Python		0.17
Smalltalk	0.17

Main takeaways: Know your tools.  Using the right tool for the right job is a great benefit, and this is true for libraries as well.  Among relatively equal choices, it is may be best to go with what is familiar.
