Though I am currently using LR4 for editing, I highly recommend Aperture too. I use an imac and before LR, that's what I was using. The interface is very user friendly and it is a very robust program. The price (in the Apple App Store) is great.
I think you would be very pleased with the program.
May I suggest that before committing to any program you need to ask what you are looking to do. Lightroom is not a true editing program. It was designed primarily as a raw conversion tool with extended abilities. It cant work in layers or many of the other true editing concepts that are needed to be called an editing app. Aperture and Elements are both god programs, but again Aperture is not a full editing program, it does not work in layers either. If you are simply looking to adjust a few settings on an image and make more generic adjustments then Aperture or Lightroom are excellent choices and Capture One Pro tops them all. If instead you are looking for a more full function editing program then Photoshop, Paint Shop Pro and even Gimp are fantastic tools with Photoshop of course being the most robust. Like many pros and advanced shooters I opt to use a program for raw conversion and another for my editing. My personal choice for raw conversion is Capture One Pro, for editing Photoshop CS6. This combination gives me even more control over my images from start to finish with each program performing the task it was designed to do. Bottom line your choice of editing options lies primarily in your goal with your images. I could never create some of the work I have by using Aperture or Lightroom so I opt for a full editing program.
To each his (or her) own, I suppose.
I imagine with the right ability a person can be successful with whatever program he chooses to use. In the end, the final image the photographer creates speaks for itself.
Exactly, success is not in the program, its in the person.
Maybe I didnt say it right the first time. The choice of program is simply based on what the intent is with the final image and how much actual editing is desired.