I have an old G4 iMac. The currently installed OS is Mac OS X 10.2.8 (6R73). It has an 800 mhz processor and 256 MB RAM. I think from reading on Apple's web site that this machine is capable of handling Tiger. Should I upgrade? Would it be better to go to Panther? Is that available? Where? Will it make the machine faster or slower? I gather from the Apple on-line store that I can only do the upgrade by buying the dvd. Is it possible to download? Are there any issues that I should be aware of before upgrading? Are there things that work now that will not work after the upgrade? Thanks!!!