Somewhat accessible spreadsheet app for IOS?

Hello all
My wife would like to start using an iPad primarily for e-mail, web browsing and word/excel documents in place of a laptop. I found some good black friday sales and before we purchase one, I was wondering how accessible iWorks really is? From the info here on apple vis, it sounds like pages will work for writing a basic document. What about numbers? I remember reading a post where someone mention sell navigation wasn't working that well as yet. Since we will be getting iWorks for free, we definitely would purchase a spreadsheet app if it was decently accessible. No complex formatting would need to be done, just the ability to navigate/edit cells and create/save documents.
Thanks for any assistance.