We've looked at Scanner Pro before and now a new 2.0 version has been released with page edge detection, image stabilization, and German, Spanish, French, and Italian localizations.
Unfortunately, it doesn't do much to address the UI issues that Erica pointed out in her original review. The UI is complicated, and it took me several attempts to even figure out how to take a picture. The screen shot at the right shows the "workflow" for creating a new document (tap the icons at the bottom, working left-to-right, to step through the process).
After I took a picture of a page of text, another menu offered to let me "crop" the scan down to particular sizes. it took a bit of effort to get the margins lined up, and eventually I just hit the "Select All" button instead.
Scanner Pro does offer a few advanced features such as the ability to create PDF files with passwords, landscape orientation, manual light/contrast adjustments, Dropbox support, and integration with Print n Share to print your scans. It also supports iDisk (or other WebDAV servers) and Evernote.
I tested the Dropbox support and it worked very quickly and smoothly. However when you initially save a document, you are only offered the option to send the file to Evernote, your photo library, or Google Docs. Dropbox is inexplicably missing from the "Send to" menu, which means that you have to step back out of the process and go to another menu to upload it.
Frankly I think the whole idea of using your iPhone as a scanner is flawed in the first place, akin to using a wrench as a hammer. If you don't have a hammer but need to whack something, a wrench will do in a pinch, but no one with any serious hammering to do would ever choose a wrench for the job. Likewise, the ability to use your iPhone to capture a piece of paper and send it to someone else or yourself could come in handy in an "emergency" but I wouldn't do it very often. For occasional, light use I still don't see any reason not to use something like Evernote which is free, or just take a picture from the iPhone camera app and email it to yourself later.
If you find yourself wishing that you could print and password protect PDF scans from your iPhone, you're much more of a power user than I am, and may find Scanner Pro worth the price. I still wish that the App Store supported time-limited demos so that people could download an app and test it for themselves before buying. I suspect that there are plenty of power users who would be willing to learn Scanner Pro's UI and benefit from what it has to offer. For the average iPhone user, $7 is probably more than they are likely to spend on an app they'll seldom use.