There are slight risks associated with the conversion to NTFS. I personally have never had any problems on any Pc's I have changed to NTFS. No one I know has had problems while doing it, but as you are making major changed to your Pc's file structure it's well worth making sure your important files are backed up elsewhere, and that when converting close all unneeded programs. Once your Pc has been converted to NTFS you will need to defrag which for this first time may take a while, that is quite normal.
I wanted to start video editing and know that fat32 limits file sizes <4GB (less than 4GB). I also found out that some older programs don't run well,if at all,on NTFS. Solution,fit a second hard drive with NTFS,then you can have the best of both worlds.Depending on your needs,but i bought a Seagate 160GB drive for ?140.