I never took advantage of upgrading from Mt Lion to Mavericks (if it ain't broke don't fix it mentality.) Should I upgrade to Mavericks before going to Yosemite or jump two generations.
Mid 2011 iMac
2.5 GHz Intel Core i5
12 GB 1333 MHz DDR3
Thanks for input.
There is no need to upgrade to Mavericks first if you intend to upgrade to Yosemite anyway. It doesnt bring you any advantages, in fact, it might add files to your harddrive that are obsolete in Yosemite.
You should definitely buy Mavericks before Yosemite is released, if you havent already done so. It might become unavailable afterwards. You can always cancel the download process and download it again later. It will remain in your purchases history in the Mac App Store.
I cannot comment on anything else, without knowing what it is you are after. If you are more interested in stability and fewer bugs, I would not recommend upgrading to Yosemite. There are bugs, there will be bugs on release and it might take a couple of months until those are addressed. Mavericks on the other hand is pretty stable at this point, so it might be worth doing an upgrade.