Recording attendance and participation using Dropbox and Cloud On

I usually take attendance and record participation on a roster I print out from infonet and then at some point I transfer all the little checks and plusses and etc. to an Excel spreadsheet so that I can calculate grades.  A simple use of the iPad in class is to put the Excel spreadsheet in Dropbox (where it can be accessed from the iPad or from my laptop) and then use CloudOn to open the file and record attendance and participation directly into the spreadsheet.

The only complaint I have with this arrangement is that Cloud on doesn't seem very responsive to the touch.  It's better with my stylus than with my finger, but there are still a lot of errors, re-dos, inadvertent re-sizings, and etc.