I'm migrating away from iView/EM to LR. Although iV/EM is more robust right now, mainly with moving and managing files, I grew very frustrated with it's very slow and buggy pace of upgrades (it's had almost no new features in a couple of years, whereas LR has gone through a couple of betas and a couple dot releases) and I have alot more confidence in LR growing and outpacing it in that regard anyway. Also, with LR I can *mostly* do everything in one program rather than two. If you are looking for something more robust, I would look in the direction of IDimager or iMatch before I would recommend jumping in with iView -- both seem far better supported and more robust, and are also less expensive. I'd have gone that way too but I'm on a Mac and those programs won't run on Mac...
WHOOPS: just saw that you're on Mac too. But, I wonder if it would be crazy to run IDimager or iMatch through Parallels or something...
Anyway, for alot of in depth discussion on this topic, check out thedambook.com
Frank