OpenOffice Calc is a free spreadsheeting software available to the public, with no strings attached. It contains many functions that are similar to those of Excel. However, there is a draw back, and that is for advanced users who like to create macro’s, the language is slightly different in OpenOffice.
It could be seen as slightly more complicated, and in ExcelHelp’s opinion, it is much less user friendly.
Apart from that, most users will not have much difficulty in transitioning between Excel and OpenOffice