"You are entitled to one Portal Named User for every ArcGIS for Desktop license that you have current in maintenance. These entitlements can be used either for ArcGIS Online (1 User and 100 Credits per license) or ArcGIS for Portal (1 user per license)." - That's from ESRI.
I can't find it now, but I read somewhere on ESRI's website where they compared ArcGIS for iOS/Android vs Collector. Said both can collect but something to the affect that "Collector was more streamlined for editing and has more features".
My takeaway from this conversation is: Collector, the product built for the ArcGIS Online/Portal platform is better than ArcGIS for Android/iOS, the product that works directly with my $40k upfront purchase of Advanced Enterprise + $10k/year maintenance. That hurts. I understand that because of my licensing I can use ArcGIS Online/Portal, but I find it disappointing that I have to. I guess Desktop Advanced, ArcSDE Enterprise, and ArcGIS Server Advanced Enterprise isn't enough anymore...