Join Date: Oct 2005
Location: United Arab Emirates & Arizona, USA
Programs: UA MM/1P, EK Ag, Marriott Life Ti, Hilton Dia, IC Dia, Hyatt Glob, Accor Pt
Posts: 4,721
Also with 50K on United, you earn Star Alliance Gold status, which allows you access to business-class check-in, lounges, and greater luggage allowance when flying internationally, which can be nice benefits.
You need more (75,000 qualifying miles) to earn the equivalent (SkyTeam Elite Plus) on Delta. I am not sure about American.