Well, that depends. I just switched from 10.6.8 to Mavericks a couple of weeks ago. I used an external drive and SuperDuper! to create a bootable clone of my 10.6.8 installation, so I could always go back to that. Meanwhile I have Time Machine for whatever new I created in Mavericks.
Anyhow, I'm now fine with Mavericks - it works for me, though maybe that depends on what computer you have (mine: late 2009 iMac 27" i7 2.8Ghz with 8GB RAM), and what applications you use. You will lose access to anything that's PPC. I still have a couple of PPC apps, and I just boot into my 10.6.8 bootable clone, and use it. No problems so far.
And so far, I love Mavericks, though I don't do anything iCloud related (don't need it).
However, we are close to the release of Yosemite, so I guess you could wait on that... but personally, I don't like to jump on the first release, so I'd only switch to Yosemite after most major bugs are worked out or at least identified, which means a .3 or so. Of course, at that point they have the next release of OS X and then you wait again on the .3 and so it goes.
So I just finally plunged in and got onto Mavericks. I'm OK with waiting for Yosemite .3, and then upgrading if I feel like it.
I upgraded to Mavericks because too many apps were no longer being updated for SL, so I had to get on with the times. But my Mavericks experience has actually been a very happy one. There's a couple of things I'm not a fan of (the pale icons in Finder I have a hard time making out - that sucks), but generally it's a huge win - especially like the gestures... makes things so much faster.
So one man's opinion - jump in, the water's fine.
