I found Geektool to be a mixed bag. The features it provides are very helpful, but the abysmal user interface and the nonexistent documentation make the learning curve very steep. E.g. I spent a whole day experimenting and googling to figure out how to call a shell script file from a geeklet (you have to use "source ~/.bash_profile" on the second line after the shebang, or the output of commands won't be displayed).
Also, while Geektool runs without problems on my 10.7.5 machines, it behaves completely haphazard on my 10.8.5 server (Geeklets not being displayed at all, clicking the "close" button of a geeklet not having any effect, etc. etc.). On most of these cases, it helps to kill GeektoolHelper in Activity Monitor.

Do not expect to get any help from the forum on the developer's website, as it is overrun with spam.

Fantastic app. It's called GeekTool for a reason; you have to already have some geekery ability to make it do much of interest. If you don't know what a shell script is, or how to write one, or are totally unfamiliar with things that live in /usr/bin, you won't be able to do much besides put images on your desktop. And most other things don't make a lot of sense then. But if you are a Geek, it couldn't really much get easier to use.

It could use improvement in certain areas. For instance, it often reshuffles the order of which geeklets get loaded first. This can ruin a carefully-crafted desktop. If you try to fix this, you can, but you run into the fact that GeekTool keeps track of its geeklets by means of hexadecimal UIDs instead of the names that you already gave your geeklets when you created them. So to shuffle their order in the plist, you have to write down which UID goes with which geeklet. There should be a box or something in the app's preferences that allow you to change the load order of geeklets, and shows you a list of them by name (not UIDs).

It would probably work smoother if there was something in the preferences that allowed the user to set a custom $PATH.

One gripe: 3.1.1 came out, and it destroyed the look of Monaco at 9pt and 10pt. They are now antialiased, where they never were before. Monaco looks *terrible* antialiased at those sizes, and having it antialiased makes things displayed look much, much less geeky :) Indeed, I'd love to see it get the ability to optionally disable antialiasing for *any* font (like in Terminal).

I tried this app a few years back and found it difficult to figure out how to use. I found the need for something like this again, and tried it again. Unfortunately, I didn’t realize I needed a different version for Lion so setting it up wasn’t working (the site wasn’t incredibly clear about that months back: It is the standalone app you need for Lion BTW. The System Prefs Pane does not work). So finally, I tried it yet again, saw the warning, and got it running fairly quickly.
I’ve read the first page of reviews: you don’t _have_ to be a geek to use this app, but it helps. If you know a few Unix shell commands and are willing to learn, you will be well rewarded. Since GeekTool free and anything you leaner can be used in the CLI, you won’t be wasting money or time.
My favorite feature is the ability to make things float over everything else. (I wish it would optionally bring things to the front automatically for a second when updated.)
I already knew all the essential shell commands, so once I got a working version, it was easy to adapt to. (Note: any command that self-updates in place such as “top” will cause problems since GT takes care of refreshing.)
I found just loading the security, system and kernel logs works well, and is light on the processor load (since displaying logs is essentially a tail command: 0.1%CPU {2.53GHz/DC} & ~30MB RAM). Also, I loaded uptime, calendar, and a few other slow refresh commands. It you find that geek tool is taking up too many resources, lower the refresh times.

If you read the sites about configuration, there are a ton of helpful tips, and prebuilt sets one can download. Try DuckDuckGo.com and look for “GeekTool” with “tips” or “configuration” if the developer’s site isn’t enough. (I noticed documentation is getting better on the dev site last time I checked about a month ago.)

BOTTOM LINE: If you want to know what is going on in your system without buying various monitoring programs, want complete configuration, and are willing to read a bit, GeekTool is well worth your time.

Like the user below me, I downloaded it from MAS and I found it to be difficult to use without doing some research. There are tutorials on the web that helped me learn this tool.

wouldn't be without it, an amazing little tool and in case you were wondering the Lion version (experimental) is here


http://dl.dropbox.com/u/1760713/GeekTool-3.0.2.zip/

Glowing reports abound for this software. It doesn't work for me.

After downloading from the App Store, it is an application not a prefPane for the System Preferences. I must open it from my applications folder. The rest goes downhill as scripts from the web don't work for me.

Something ain't right and I think it's me.

It's really great, however if a display the output of

top -ocpu -FR -l2 -n20 | grep '^....[1234567890] ' | grep -v ' 0.0% ..:' | cut -c 1-24,33-42,64-77

it doens't justify it, even if the terminal does (this holds also if I put the above inside a script).