In the form of a PECL extension. Currently min PHP 5.1.2, so no 5.3 bells.

http://www.php.net/manual/en/book.yaf.php

Some current HN discussion can be found here http://news.ycombinator.com/item?id=3195690

How does this impact the framework landscape for you?

Is this appearing just a bit too late?

Will it move from PECL to core (as many things have over the years? PEAR->PECL->Core)?

Had you seen this coming?

Are the comparisons made with ZF (on HN) fair?

Are you going to try it?