Harit, in his own thoughts…

Both services provide form interface for end users – to collect some information may be for surveys or for feedbacks.

What so good?

Wufoo – a really impressive interface, wide category of field types and validation, email updates, customizable and much more. (http://wufoo.com/features/)

Payment integration and security (SSL) is perhaps most attractive feature.

GDocs Form – a very simple, easy to use, partially customizable, directly associated with google spreadsheet (like excel sheet), simply publishable / embeddable like wufoo. It’s free!! No limitations ofr posts per month / day.

Again, Forms is a part of Google Docs. So naturally, I can’t expect something more like wufoo – a perfect solution for online forms and integration.

Then what’s bad?

Wufoo – free edition is limited to 3 forms and 100 posts/month only. Need remember another account (wufoo is another service not associated with any other) – whereas google docs are part of google services, so not required for another sign up.

GDocs Form – not really impressive interface, just simple. Can directly share the collected data (essentially spreadsheet) for collaboration.

Conclusion…

If user requirements is not much complex and security is not essentially in consideration, Google Docs and Forms are good option, whereas if security and branding is important – wufoo is the best choice among two.

Few advanced features like validations of input as well as online payment is only achievable in wufoo.

Thanks to Mr. Karania - http://www.ashokkarania.com/blog/2008/09/great-tool-wufoo this post drove my attention to wufoo.

Wufoo – http://wufoo.com/

Google docs (Forms are part of this suite) – http://docs.google.com/