I have used Python. It is simple and powerful. One of the crazy things about python is ipython shell. I don't know Perl. I have heard that it is an excellent scripting language. Which one do you think to be a better programming language and why?
I would vote for perl, as I am using it for quite a long time. Since both have extensive library it would be hard to say which one is better. The problem you are interested in would suggest what to choose. Any of them would do a great job.
There's no absolute answer to that question. It depends of your application. I know the two languages and, what I would point out is that, very broadly, for application involving text parsing use Perl, for computing stuff, use Python. Of course, you could use the two for any of these applications. That's one hint! Another hint is: use whatever you feel confortable.
Perl is more concise. Python is more readable. They do mainly the same thing and which is better depends on whether conciseness or readability is more important to you.
Perl over Python any day! But over time I've realized that if it is just text parsing that you need to do, the LINUX command-line provides excellent one-liners for any and everything you can think of, just a matter of exploring.
Python is a better choice. In fact, object-oriented features have now been incorporated in to Python, which makes it more richer in handling and processing biological data, bioinformatics data. It also finds expression in computer science-related projects.