it's generally free, and that's about it
some believe it's better than commercial software...but only if it's objectively sound...
ie., flaws can theoretically be patched quicker
and that's the only REAL thing that can be said about it...all others are purely subjective
some people see it as a standards issue, closed vs open, but that is more semantics. Like file formats...why use X commercial format when you can use X open source format.
just use this as a guide...read when you have time and see which side of the equation you fall on:
Live Search: benefits of opensource vs commercial
it doesn't matter to me if something is commercial or open source, so long as it fits what I am looking for for the current time being. Namely if I have no cash and need software...I use freeware open source as opposed to pirating.