I've used both Aperture and Lightroom. Some things I like about both programs. Recently became much more aware of the distortion in my photos. I usually use a 35mm prime for most of my photos. Never really noticed the distortion before (I think my brain just corrected it for me and I wasn't able to "see" it in my photos). I've tried to correct it in PS (or LR4) and often wasn't happy with the results. Possible just lack of experience. But my corrections seemed "off" somehow. Just upgraded to LR5 and played with it some today. One of the touted new features was distortion correction. It seems to really work. Doesn't require any futzing around, just click a button and it's fixed. Haven't used it enough to know how often it's a hit versus a miss. Subway in NYC near the Cloisters that I shot this weekend. No distortion correction. Did the B&W conversion with Silver Efex Pro 2 from Aperture. Auto-distortion correction in LR5. Then used Silver Efex Pro 2 for the B&W conversion.