Should I upgrade to the new OS?
Maybe. I'd suggest using the 1, 2, 3 upgrade question approach before you do:
1) Can I get my work done on my current OS w/out significant problems?
2) Are there any known issues on the new OS with software I use regularly?
3) Is there something I need the upgrade will provide?
If you said no, no, yes to these, then upgrading is a no-brainer.
If you answered anything different than above, it's a yellow flag: proceed with caution.
Mind you, this doesn't mean that one shouldn't do it, only that one should investigate the upgrade as it relates to their answer to these questions.
What one usually finds is that there are features - including performance improvements - that one wants as opposed to needs. This is a perfectly valid reason to upgrade. But the decision to upgrade based on wanting as opposed to needing should be made with the clear understanding that all upgrades have the potential to go bad. Measure the risk against the reward and be honest with yourself.
As for me, I care more about getting work done than any new feature. I've waited anywhere from three months to a year after the release of the last three OS upgrades from Apple.
Whatever you do, just remember to NEVER do an upgrade without a solid backup of your system.
After that, rock on with your bad self and your shiny new OS.