Okay, I officially love this program. Love.
It was already great by default, but after making adjustments, it is now pure unadulterated sweetness.
FINDER:
CPU = 0% (when not using it)
Real Memory = 19.80 MB
Virtual Memory = 151.11 MB
PATH FINDER:
CPU = 0%
Real Memory = 28.61 MB
Virtual Memory = 224.58 MB
I have a 1GHz G4 PowerBook with 1.25 GB of RAM. I don't know how these numbers add up or compare, or whether it's supposed to be less than 1.25GB since that's all the RAM I have, but I can tell you that I don't notice any significant difference in speed.
All I know is that MS Windows Explorer had Finder beat (gave more useful info when you needed it, but truthfully, I'm not happy with either), and Path Finder beats both of them by a long shot.
THINGS I LIKE:
1) Spring loaded folders in Finder are nice. However, if you're dragging and dropping, there is a little area in Path Finder where you can temporarily drop a file you want to move (aka: the "DROP STACK"), then you can proceed to the folder of interest, and drag the file from the DROP STACK to that folder. It makes dragging and dropping
A LOT better.
2) Column VIEW: Its what I use(d) in FINDER because I like being able to view the parent folder if I'm in a subfolder (which you can't do (well) in LIST view). When using Windows Explorer (*hisssssssss*), I LOVED using LIST view. Now with the path of the folder I'm in easily visible, I can use LIST VIEW, which I like more.
3) You can also use a "BRANCHING" organizing system (sorry, don't know what else to call it) like in Windows Explorer where you can see a parent folder, click on it, and view all subfolders and files within that parent directly, all in one window. You can also see the sub-sub-folders and files. Its similar to COLUMN View in Finder, except there aren't different organizing columns to separate the sub-folders from the parent folders.
4) PREVIEWING files is better, especially for Word and text documents. You can actually scroll through documents and read all the text from within PATH FINDER's "preview" window.
5) Use Terminal, convert images, compress and decompress (ie: "zip") folders and files quickly, show invisible files, show package contents......all with one clicks.
6) Much more customizable.
7) All open apps, and all running apps (ie: apps whose window you closed but didn't "QUIT" from completely) are listed on the left side, and you can quit them easily from there.
PATH FINDER just gives you all the info you need. It does everything FINDER does, and more.
Admittedly, I downloaded and loaded some serial key from the internet to use it (I was afraid that I wasn't getting a full version with all the features......sorry

), but I'll definitely buy version 4.0 when it comes out.
It'll have TABS!! The version I just "reviewed" was version 3.2.2.