To Panel or not to panel- that is the question

Hi everyone.

I wanted to know people's experience with Panel module and Panel 2 module.

I see you can use Panel 2 to theme input pages.

I am developing a site just using good ol' fashioned tpl.php files, views, and css.

What are the advantages to using Panels?
How much flexibility do you have to customize the panel?
What are the performance implications? It looks like a large module or set of modules.
Has anyone migrated their site to use panels?
I am using views heavily and am just now really beginning to understand the power in the Views abstraction. Does panels replace this? enhance it? or does it just let non-technical people do a lot of the technical stuff through a UI?

Thanks for your thoughts on this.

Just a little confused.

A