iPhoto as an editor can tide you over for a while. For organization, I don't trust it not Apple. If something goes wrong in iPhoto its tough to rebuild. Not nearly as robust as Aperture and more tools in Aperture. Perhaps the later versions are better, I abandoned it after the second forced change by Apple. That's my second issue. Apple will continue to introduce new magic within its iOS devices. Some of which will impact photos and who knows how many more library or OS changes will be forced upon you. For me, with 5 Mac's in the family running various flavors of OSX, it was a pita. As someone else stated, I'm also starting to rid myself of Apple software.
As far as Lightroom goes, its solid but needs CPU to run smoothly. My main machines for photo editing are a 2.8 c2d, 6 gb ram iMac and an i7 1.7, 8 gb Air. Neither run LR remotely as smooth (GUI) as my default Aperture.
Don't ignore C1. Its a more Mac oriented interface than Adobe and shares many of the Apple terms that are used in both Aperture and iPhoto. I found it a very easy pickup but decided not to use it as auto masking is not enabled with my Fuji XTrans files.
I'm waiting to see what Photos looks like after 3rd party developers have had enough time to indicate support. I find with both Nikon and Fuji, I prefer the initial renders both Apple and C1 provide. Not saying it can't be done with LR but its more work.
For cataloging, Aperture is the star. Simple, fast, does it all. My 600 gb referenced library is solid as a rock.