Pros and Cons:
Steam:
+Faster Downloads
+Steam License Mangement and Steam UI Features
-Single Branch Line (Doesnt Hold Separate Installs for Open Beta/Release)
-Delay of Individual Modules Availability
-Delay in License Keys Being Merged to their Database
-Does not Work with Black Shark 1 + 2 Upgrade.
ED:
+Works with every module
+No delay in Module Availability
+No delay in License Key Validation
+Separate Installs for Open Beta and Release Branch
+Command Line Options for DCS_Updater
-Slower Downloads when Server is Loaded
I'd add another + for Steam. It's extremely easy to manage add-on modules. No mis-matching versions, no confusion.
That in itself makes it better than ED's downloader for 90% of players who don't feel like researching how to install a game.