I'm just an average user, so I can't compare this utility from a technical viewpoint to the other thousand that you can find out there (many of them for free).
What I do know though is the fact that none of them is as clear and simple as TinkerTool System.

Besides having a nice and effective GUI, this app tells you exactly what is going to do every time you select a task, letting you know about the risks and the reasons why you should perform a determined action, instead of just offering you the option to do it.
This is really important when it comes to this kind of application, since many people rely on them even when it is not needed, creating new problems instead of solving old ones.

Simplicity does not mean lack of power, as TinkerTool System has a wide set of options that range from system maintenance to various file operations and system tweaking. It even offers you to install a standalone version, useful in case Mac Os X can no longer start.

To sum up, if you are looking for an all-in-one system maintenance utility on which you can always rely and you have 14 bucks to spend, look no further.
This application has much to offer, and the price you pay for it assures you a long-term support.

Ive been using tinker tools since the first g5 iMac and love it, some people say its too complicated, I tell them, move on.

I had long ignored TinkerTool System since I had been happy with Onyx and didn't see any value in TTS. A year or so ago, I gave TTS a new whirl and soon enough was sold on it. It really does have a number of features not present in Onyx, and one thing that TTS excels at is explaining everything it does and why or why not you should use a certain tool. Onyx does to an extent, but TTS seems to be more thorough.

Beyond helpful explanations, TTS does have a couple tricks up its sleeve that no one else has, or is available in apps that are not actively maintained. For example, its ACL Permissions tool can perform operations that I've only seen before in a couple other apps: ACL Fix and iRepair, neither of which have seen updates in years. And before anyone says "Oh you can just do that in the Finder", no, not to the extent that these apps can. When Snow Leopard came out, there were wide reports of permissions bugs and I got bitten by it myself. ACL Fix was what eventually fixed my problems, and it appears TinkerTool System should be equally capable. TTS has the advantage in being actively maintained and I can count on it in the years to come.

Code Thinning is one that can be done with TrimTheFat for free, but it hasn't seen an update in 5 years. Or you can go with XSlimmer, but that costs 15 bucks… JUST to do that. TinkerTool System costs about that, but does MUCH more.

The Uninstallation Assistant in TTS is superior to AppZap, iTrash, and all the other similar ones. Reason being is that it will optionally seek out and delete the extra components in all user accounts, not just the one you are logged into. I've not seen that ability in any other uninstaller.

There's more to mention, but it comes down to this: TinkerTool System is a more complete system maintenance utility than anything else out there. Some of its tools are more thorough than the competition; are more actively maintained than the competition; are better explained; and is very reasonably priced. If all you need from it are the same tools offered by Onyx, then by all means go with Onyx (an outstanding tool in its own right). But TinkerTool System does have more to offer… you just have to decide for yourself if it's worth the 14 bucks to have an actively maintained utility that can replace half a dozen other tools that may or may not be freely available otherwise.

I would really like to purchase TinkerTool System but I simply don't see what it can do that OnyX can't. I tried the evaluation version for the five times it lets you use it (which isn't quite enough) and tried to compare it to OnyX. Perhaps there are some features it has that OnyX doesn't and I'm just missing them. If so, I'd be happy to buy it. Simply getting rid of the startup chime isn't worth the price...I already gotten rid of that with a simple Terminal entry. Any other virtues it might have? Thanks.

This application was worth the nominal fee if only to find an effective way to silence the chime you'd otherwise hear when you boot. Of course, there's much else to make this worthwhile, including a wealth of cache-cleaning tools.

Not sure what's going on, but I get a message at launch saying the permissions settings or other part of the security component has been damaged, and it must repair itself. But it never does, and I keep getting that message at every launch. Repairing permissions doesn't fix it.

In the short time it took for the component to get damaged, I didn't run many apps, so maybe I'll be able to figure out which one is the culprit.

I use both TinkerTool and TinkerTool System, and appreciate the efforts that have gone into developing these fine programs. With this new update, something "odd" has surfaced. When I attempt to clean caches, the Safari button is "grayed-out" and it will not allow me to select Safari. I'm using the latest Safari (3.1.1) and wondered if that affects it. Any ideas here? Why am I unable to select Safari? FYI, Shiira is "grayed-out" as well, but I was allowed to select all other browsers. Still, I use TinkerTool System each day at shutdown, and love the application.