Jv16 PowerTools 2011 ($30, 60-day free trial) is a utility suite which includes many useful tools for performing all kinds of system maintenance, from temp file cleanup to startup management. Unfortunately, it also has a number of issues, giving it the feeling of something rushed to market a little bit before QA was finished with it.
Let's start with a rundown of what jv16 PowerTools 2011 does: Almost everything, really, at least in the general category of system tools. There is a registry cleaner, a duplicate file finder, a temp file remover, history cleaner, startup program manager, and windows settings manager. There are also less common tools, such as a file organizer (will sort files into new directories based on their characteristics), an uninstaller, a registry search tool, an undelete tool, and more. The tools are organized into categories, and there are high level tools that consolidate several related low level tools into a single dialog box.
JV16 PowerTools 2011 offers a lot of flexibility to the user. Many of its features are set to "safe" defaults, so they will not delete or change vital system files, but it will also let the user override these settings. Rather nicely, it warns you if you're about to do something that's particularly risky, and, in most cases, it will back up files or registry entries you're about to tamper with. (This won't help if you manage to make your computer unbootable, of course, but it can come in handy for lesser disasters.)
Based on the feature set alone, I'd have no problem giving jv16 PowerTools 2011 a high recommendation, but unfortunately, how a program does something can be as important as what it does. The first time I used this version jv16 PowerTools, simply accepting default values, it completely hung. (I have not been able to replicate this behavior, so it may have been due to an external factor.) Since then, I've been confronted with many minor issues that add up to a feeling of sloppiness, the absolute last thing you want to feel when using a program that's rooting around in your system's internals.
A few examples: When the uninstall tool can't find the source folder of something you have told it to uninstall, it does nothing--it doesn't even pop up an error box or let you know it's even acknowledged your click. In the file finder, the "what to find" field was disabled until I unchecked and rechecked the "Files To Find" checkbox. When I added the "Date Modified" column to the results of the file finder, it did not populate itself; when I added the "Size" column next, then, both columns were populated. The "uninstall" tool allows you to make multiple selections, but if you then try to uninstall, you get an error saying you can select only one program at a time. I'm fine with the one-at-a-time limit, but then why not dim all the checkboxes after you've picked one, rather than letting you scroll through a list of dozens, selecting all the ones you want gone, then making you unselect them all? I'm not going to list every nit I found to pick; they're all of a similar nature: Individually minor, but the number of them is worrying.
Older versions of jv16 PowerTools met or exceeded my expectations in this product category, so I was looking forward to the latest iteration. Unfortunately, the issues noted above mean I can't recommend this edition until it's gone through another patch or two.