So the Facebook Subscribe button is pretty great for those who want to maintain their social life and start building a public persona, and is a great alternative to pages for those people.
But switching to this alternative loses the brilliant one-click Like button for websites.
Do Facebook offer a solution which allows you to add a subscribe button for your website?
It's pretty easy, facebook offer a generator here http://developers.facebook.com/docs/reference/plugins/subscribe/ essentially it's a like button with different text.
I am not sure to understand what you mean. The "Facebook Authentication" button is totally different from the like/share button and not an alternative.
http://developers.facebook.com/docs/guides/web/
I personally have both on my website, you can also add Facebook comments to posts linked to share/posts with optional facebook registration for your guests.
