The rest of the iPad spreadsheet editors
DataViz's $16.99 Documents to Go Premium offers the basics, but no more. It's languished for several years, so it's not a good investment choice (the recent update was trivial). It does not support printing or PDF export.
Google's Quickoffice (free with a Google account) is very Excel-like if you edit local files, but its functionality is too limited for cloud-stored files.
Infraware's $12.99 Polaris Office 5 has a competent if basic set of spreadsheet features, but its user interface is awkward.
Artifex's $9.99 Smart Office 2 is simply unusable due to a very poor user interface and limited capabilities.