Hi, this is Feran with the Internet Explorer Outreach Team. As long as you meet system requirements you should have no issue upgrading to IE8. IE8 is a more secure and reliable browser. You can read more at the IEBlog - http://blogs.msdn.com/ie/ and check out these reviews regarding its security features - http://www.pcworld.com/article/161587/is_ie8_actually_safer.html
http://www.itworld.com/internet/67113/ie-8-its-security-worth-download

Also at this time if you download IE8 from http://www.browserforthebetter.com?ocid=ie8_sm_a Microsoft will donate 8 meals to Feeding America.

Thanks,
Feran