I'm in a D-65 Lightroom workshop for 4 days. Starting day three, these are my opinions of the moment.
There is probably no more powerful photo database application than Lightroom. Expressions Media is a faint shadow in comparison. However, it takes forever to build the 1:1 previews that make it such a useful tool. Friday night I pointed the app to a hard drive of 40,000 images. I am not certain the ingest will be complete by the time I return to the office on Monday morning.
As an ingest app, it is powerful but perhaps too complex. You can run off in a ditch if your settings aren't exactly right. I think Photo Mechanic is still the best ingest app. In Lightroom here is a bug that will mess up your sequencing if you delete some images and rename the batch later.
As a developing tool, I'm still on the fence. The adjustment tools are identical to those in ACR (what you use in a Bridge-Photoshop workflow), but I think they're not as convenient to use in Lightroom.
One small, but key example. In ACR, you can manipulate any slider by hovering above it, and adjust the setting from any place in the active area. You don't need to be precisely oriented on the pointer. It is a small detail, but it makes it convenient to drop down from slider to slider without needing to orient the mouse left or right. Lightroom lacks that feature. When processing hundreds of images this will matter.
Another: A habit I have in ACR is to select a group of images, and apply the same setting (like color temp) to all of them. I use the sync button all the time too, which does the same thing, but I use it for global sync of all settings. Lightroom lacks that dual sync capability.
I have a big investment in the muscle memory of ACR. I'm reluctant to relearn another system. Why I am considering it is the maddening wait when loading large image folders in Bridge. What I don't know yet if the maddening wait for preview load in Lightroom is an improvement. In Lightroom I think it's a one time event. In Bridge the images rebuild after any developing change.