Should variables contain apostrophes in templates?

[PinkMilk]

Should variables contain apostrophes in templates?

What I mean by this is should they look like this:

<if condition="$post['fieldx'] == 'lala'"> ....

or

<if condition="$post[fieldx] == 'lala'"> ....

both seem to work and I have seen many people use with and without in examples, as well as in the templates themselves, but I would like to know if one is safer then the other, whether it is simply user preference or something else entirely.

Note to mods:
I have accidentally posted this in the wrong forum, it should be in the vB3 General Discussions or vB3 Programming Discussions.