This is pretty much the only bug I'm aware I kept running into in Aperture. (the external edits not being reflected in the previews thing)
I love Aperture, and tried Lightroom out comprehensively - loved that too. Also tried Capture One Pro.. They all do much the same stuff its insane to say people should be using one over the other. It's really about how one responds to the features, interfaces and possible workflows. I'm so efficient at doing what I do now in Aperture I'd have to find totally new ways to do the same things in LR and I prefer the way folders, metadata etc are handled in Aperture.
Everyone's going to like different approaches to single tasks.