Originally Posted by
mecabq
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.
With AA you get Oneworld Sapphire for 50k, which is by-and-large the same as Star Gold.
At 100k, you get OneWorld Emerald, which gets you access to the first-class lounges. (With Star, there is no status-based access to F lounges, though some individual carriers allow their top tier elites in their own F lounges. (SQ allows PPS Club Solitare's into the SIN F loung ewhen flying SQ, I believe, for an example. Based on your travel patterns, I don't think you have to worry about making Solitare, though...))