Google-watchers may have been titillated earlier this month by the news that the online giant had reached its tentacles into yet another realm: legal software. By contributing to a $18.5 million cash infusion into Rocket Lawyer, a website that helps businesses and individuals create their own legal documents, Google Ventures and Investor Growth Capital appeared to be lending its stamp of approval to the online legal software industry.

But consumers looking to create a will on Rocket Lawyer or other legal software products need to be aware of their limitations. When Consumer Reports Money Adviser recently analyzed and judged three top-selling legal software products—server-based LegalZoom and Rocket Lawyer; and Quicken WillMaker Plus (available as a download or CD-ROM)—we found problems with all three. WillMaker Plus, which is compatible only with PCs, did the best overall in creating the wills in our test. Rocket Lawyer came in second. All three are better than nothing if you have no will, but inadequate except in the simplest situations.

Our test involved creating three very different scenarios: the husband of a simple nuclear family, a widow with grown kids and a live-in boyfriend, and a twice-married father of five. We input their information, including their bequests and other wishes, into the three software products. (The interview process is similar to that of tax software like TurboTax and H&R Block At Home.) We then had a prominent professor in estates and trusts review the results, as well as the legal information the software products provided.

Among the problems we found in one or more of these products: outdated information, insufficient customization, incompleteness, inability to handle some tax issues, and lack of flexibility. WillMaker Plus, for instance, made it hard for us to distribute property the way we wanted to. On the other hand, we found too much flexibility with both Rocket Lawyer and LegalZoom. Both allow you to edit your will in ways that could create contradictions within the document.

Overall, WillMaker Plus and Rocket Lawyer made good simple wills. But, our expert determined, consumers would be better off consulting an attorney for more complex cases. And your case may be more complex than you think.

One good use for this software: education. Going through the interview forces you to think about issues such as, "Who should be the alternative executor?" in a way that simply reading a book on wills does not. Taking a practice run on either Rocket Lawyer or WillMaker—and determining in advance issues such as who will be the guardian and who will get Aunt Minnie's brooch—might save you time at the attorney's office.

And as anyone dealing with an attorney knows, time is money.