I'm considering learning a new language as an alternative to PHP. I'm considering Python and Ruby. Which one is a better language based on the following four criteria, and any other qualifiers you may have?

Which is more stable?
Which is more scaleable?
Which is more secure?
Which is easier to learn?

EDIT:
Keeping the original question intact, I'd like to add one more pair of questions.

Which is quicker to code with?
Which is quicker to learn? (Based on personal experience only please - to avoid holywars.)

EDIT2:
Sorry for not clarifying - mostly web development, some desktop programming would be a nice bonus.
No significant difference on the first four criteria.
No significant difference on coding speed either - you're going to be slow in both at the start, then you'll get faster. Ruby may be slightly better at managing libraries (Ruby Gems) but Python probably has slightly broader library coverage. No big deal either way.
Coming from PHP, I'd guess that Python might be slightly quicker to learn. That might be a reason for choosing Ruby - you might learn a little more.
There are a lot of "mights" and "slightlys" there. That's because the two languages are much more similar to each other than either is to PHP. Neither is particularly hard to learn - I'd suggest spending a little time with both and then going deeper with the one you prefer.
Ruby or Python instead of PHP?