Upload & Sell: Off
I recently got LR (4.2) because Aperture 2 wouldn't read the new 5D III files. Had to use DPP to convert the 5D III files to a TIFF, which Aperture would read. Cumbersome, and big files.
Toss up between going to AP v3 or trying LR 4; I went with LR 4 and have had no trouble with the 5D III files - they import straight into LR. I use an external USB card reader for CF, and the built-in SDHC card reader on the side of the iMac. (OS 10.6.8)
I also got Kelby's book for LR - I recommend it for those new to LR like I am. Starts you off from the bottom, and I found that LR wasn't so intuitive. Don't know if it will help you, but in his book he suggests making a folder within the 'Pictures' folder and calling it 'My Lightroom Photos' and pointing LR to that folder to store all your imports.