Find Any File searches your local disks for files by name, creation or modification date, size, or type and creator code (not by content, though). As there are other tools with a similar search operation, here are the special features unique to Find Any File:
Has a new hierarchical view of the found items, making it much easier to browse 100s of items.
Can run as root user, finding really any file on your disk, even those that are hidden from normal users.
Can save queries and run them again later.
Is quite fast: About 10 times faster than EasyFind 4.0.1 when searching for a file name (Mac Pro with 2 million files, searching "httpd.conf": EasyFile: 150s, this app: 15s)... More Info »
Unlike Spotlight (i.e. the Finders Find command), it does not access a pre-built database but searches the chosen volume directly. This allows you to find any file, even those inside packages and others excluded from Spotlight search. Hence it is great for finding system files, for example.
On the other hand, it may take a little longer than Spotlight, and it is only fast on HFS(+) volumes. But even on mounted network volumes of a Mac OS X server it can still be surprisingly fast.
Hence, this is not an entire replacement for Spotlight but it can come handy in certain, if not many, situations.