I have been promoting the dual use of Linux and Mac OS since I started this blog. Each OS has it's own set of strengths in terms of certain tasks and capability. In terms of content creation like graphic arts, video and audio work it's hard to beat Mac OS. It has so much more capability right out of the box even with an old version of Photoshop or other established content creation apps.
The clear main strength of Linux today is that it is far more secure for internet and network tasks. I see constant kernel, general security and browser updates in Lubuntu 12.04 and 12.10. The same can be said for Debian. In terms of OS X on PowerPC there is zero development going on from Apple and because it's all closed code (other than Darwin) it will stay that way forever. For secure online and network activity Linux or BSD is an absolute necessity on the architecture. Any practical and sane user would not even see it as an option.
When it comes to security on Mac OS PowerPC there is nothing any of us will ever be able to do now to improve this at the OS level. A wise user helps in terms of habits and actions but this can only do so much with such a mass of neglected code that cannot be fixed. Updated browsers like the TenFourFox family or Leopard Webkit can only help you at the browser level. It is still possible to exploit OS level stuff with the right cracks.
The good news for the people who are in the creative arts game is that virtually everything is safe and secure in this regard. The one exception would be Flash content for obvious reasons. I mention these people specifically because they make up a majority of Mac users. Some of my clients own audio or video production companies and several of them still use PowerPC systems as old as a beige PowerMac G3. In the audio industry specifically there is a lot of running old apps on old hardware that happens. I normally see more G4 and G5 towers than anything else. The old adage that you have proven methods with certain tools and they never let you down so you stick to them. If it's not broke don't fix it as they say. I once saw a video of an Ice T interview inside his studio around 2008. He was still using a PowerMac 8500 and System 7 for all his sequencing. He said the reason was that it's the most reliable tool and hardware/software combo with the best results he had ever used.
Breaking it down
Linux/BSD
There is really no need to get overly wordy about what is best for what task. Keeping it simple keeps the lines in the divide clearer.
Linux and BSD is where it's at in terms of any type of real software development on the architecture looking forward. The capability and growth is only as limited as the audience of users. With the proper skill and ability anything is possible in the Open Source OS world. This is something you will never get from any version of Mac OS or Windows. The true barrier for most is the not so simple route to making thought come to life in software.
Open OS like Linux and BSD are the only totally open limitless option for even brand new hardware because of the limitations of the Mac OS and Windows world. On PowerPC these are the only OS still developed today.
There are things like MacPorts and older versions of Xcode to bring open apps to Mac OS PowerPC but you are still stuck with all the abandoned OS code that you couldn't change even if you were the worlds greatest software developer.
Security is really only important online and in big networks so these areas are where PowerPC users should look for every day type solutions. Linux and BSD are so much more prepared to protect you online even when compared to modern Mac OS and Windows. When it comes to things like internet banking I NEVER use Mac OS anymore. Only OpenBSD or Lubuntu for me. Even with an updated browser you can't be sure of 100% security in OS X PowerPC because of all the OS code supporting the browser not working to modern standards.
PowerPC hardware is cheap enough these days that you could have a dedicated Linux or BSD machine for online activity and another system dedicated to Mac OS. The great thing about using both OS is it will give you Mac familiarity to keep you sane while you drink from the *nix fire hose.
Mac OS
It is getting long in the tooth security wise on PowerPC but there are so many common Mac tasks which are not affected by this at all. You will be able to do all the non-connection based tasks with no worries for as long as your computer runs.
I wouldn't be shocked at all if I was still using Photoshop CS3 and Pixelmator 1.5 on OS X in 10 years. Both are from the 2007-2009 era but are more than capable for really anything. I know professional graphic artists that still use Photoshop 5 on OS 9. Newer isn't always better for everyone. As with most software each version brings more fluff than anything in most situations. The truth is that there is no replacement for a perfect hardware/software combo that never lets you down. It helps you work with pure confidence and that is what it's all about with creativity.
With things like simple video playback I prefer OS X myself. As a CorePlayer owner and user of other greats like VLC 1.1.12 and MacTubes I get all I ever desire from Leopard in terms of video enjoyment.
Gaming is another area I always look to Mac OS for. The Open Source world leaves a lot to be desired in regard to gaming. As I write about in my gaming article a while back there is a lot to be had in terms of great old games with some as new as 2006.
In closing
For those that have yet to take the Open OS plunge on their PowerPC hardware I strongly encourage you to try it out for at least internet activity. This is one of the easiest tasks to use Linux or BSD for. On Lubuntu you get an up to date OS combined with FireFox 18 and Sylpheed (or modern Thunderbird if you prefer) along with almost daily kernel updates. This is the only avenue for us now where there are people actively working to keep us safe and secure at the app and OS level.
Don't ever feel you need to give up Mac OS. Even on PowerPC it will be a great tool for many tasks where security is not an issue. Embrace it for all the reasons I mention and add your own in as well. It's still great for daily browsing of trusted sites where security isn't a concern when you don't need https.
I know I will add more to this but I wanted to get something out since it has been six days since the last post. Share your best OS for the task thoughts in comments.