Most of the iPad Office apps have limitations - it's almost inevitable - but there are often/usually work arounds.
For example, Apple's iPad iWorks 'Word' app, Pages, doesn't have in-built a mechanism for inserting super- and sub-scripts or handling footnotes - but there are well-known - effective, though ugly - workarounds that you can use if you're in a fix!! Similarly, it has no in-built support for many frequently used symbols - but, again, there's a 'fix' for that too!!
Of course, it would be nice if these Office apps were fully Word, PowerPoint or Excel compliant but, realistically, I don't think we're likely to see that.
Tim
Scotland