Zipping folders

I was going to extol the virtues of compressing folders in XP and Vista by using the operating system to zip them, particularly when backing up your data or sending files by email. But after some reading and personal experimentation I am changing my tune.
Firstly, whereas in the past you needed a utility like WinZip to create compressed or zipped folders, since XP you have been able to do it without a utility. It's a bit clumsy. You have to create a new zipped folder (right click / New folder / New compressed (zipped) folder), and then copy documents into it. Or in Vista, you can select documents, and then right click / Send to compressed folder. So far, so good. The trouble is, from user forums on the internet, it is apparent that when you subsequently try to access the documents in the new zipped folder, all sorts of problems can arise. Many have complained that the folder contents are no longer visible, or cannot be opened, etc. It appears to be a worse bug in Vista than in XP, but I can't in all honesty recommend that you use this feature. Another issue: the amount of compression you achieve is very small, particularly with photographs and pdf documents. Typically, you get miniscule difference with a jpg image (which is already compresssed by the format), and a test run I did on a pdf file resulted in only 7% gain. The best gains are with Word documents and the like, which compress by big margins.
Fortunately, there are good alternatives to XP and Vista's efforts. Probably the most popular third party program over the years has been WinZip, but it is not free, although the trial version seems to run for a long time. A free open-source program is 7-Zip, which I have used without any problems.
Given the slightly arduous process involved in zipping, I tend to use it mostly to send documents by email, when it is a handy way to provide a container for multiple documents which I want to keep together.