Open office is the best alternative of Microsoft Office. Open office is one of the best office suite available free. Initially it was being developed under the banner of Sun Microsystem but in 2010 Sun Microsystem has been acquired by Oracle. Latest version of OpenOffice suite has word processor, spreadsheets, presentation, graphics and database. OpenOffice supports a lot of plugins and more than 90 languages. You can do almost everything of your need.
Its interface is quite similar to MS-Office’s interface. Which will make easy to adept it. its download size is still small (about 150 MB) compared to MS Office. It also supports MS-Office file format which means you can easily create MS-Office files and share to some one who have MS Office.
CNet has given it 5 star ranking in Office suite category and people had downloaded it more than 3,343,500 times, which shows its popularity.
Finally OpenOffice provides you a strong reason to give it a chance and for those who uses pirated version of MS Office, OpenOffice can give more than a pirated MS Office.