10-17-2014, 11:11 PM
space-time wrote:
[quote=Kate]
...
I need a copy to update the old computer that is still on SL, then at least I would have a working computer in case yosemite screws everything up!
Kate
flash news: the old computer still on SL has the best OS Apple ever made

That no longer receives any updates from Apple and won't run modern software.
...
Mavericks is a huge jump from 10.6 and adapting to the interface changes (or correcting the default System/Finder settings to make it useful) after using 10.6 for so long is likely to be a painful and long process.
Yosemite revamps the whole thing again.
Given that, if your Mac is fast enough and has enough RAM to run Mavericks well (I recommend having at least 8GB RAM), you might as well make the leap to Yosemite. It won't be harder to adapt to than Mavericks and has the same system requirements.
I suggest that you get another external hard drive and make a bootable clone before installing Yosemite so that you can easily revert to 10.6 if you feel the need.