questions about avatars

hey guys.

I was just trying to implement the avatars plugin, and use blog avatars and user avatars in the appropriate places, when it struck me that I don't really need those.
To be honest, right now I am contemplating using the general gravatars instead. what are you using? is anyone just content with the gravatar service or is everyone using this plugin?

I'd love to hear some thoughts to help me make up my mind...

two additions:

1. I don't fully udnerstand these functions: get_blog_avatar(1,'32','identicon'); does this i.e. fetch identicon and thats it? I can chose between: 'mystery', 'gravatar_default', 'identicon', 'wavatar', 'monsterid' so which one is the blog avatar my user uploaded? or is it trying the blog avatar first, then one of these? Meaning: is there a fallback in case there is no blog avatar?
2. regarding the theme pack, I rememebr reading somewhere, the avatars plugin is fully itnegrated, does that mean if I don't use the avatars plugin, gravatars will show or rather nothing?