If version 8 works for you then I would not recommend the upgrade, because I gave 2013 a try and have to say that the negative reviews are true. With 2013 you are forced to install a "Pro" test version, then you are forced to use it for 8 hours and can't skip it. Even after the evaluation period is over, every time you launch Sketchup a license screen pops up instead of the file. When using the orbit tool additional license error messages pop up. It gets really annoying. Sketchup 8 on the other hand works perfectly, with no errors or license crap. So I uninstalled 2013 and went back to 8!
