I am in the process of looking for flights to return to Europe with my family in a couple of months. There is not a lot of availability just yet, but what availability there is all entails the first leg of the flight being on US Airways. After that, it connects with Lufthansa to Germany. The problem is that if our first leg is on US Airways, none of our Star Gold benefits (extra baggage, priority check-in, priority boarding, priority security lane) will apply (since this trip is after March 30th).
So, if you have travel booked on Star Alliance partners but will check-in with US Airways on your first flight, just remember that you will not receive any Star Alliance Gold benefits after US Airways leaves the Star Alliance. If you are booking award travel on United before March 31st, just remember to look at the first carrier of your ticket to ensure you will receive your Star Alliance benefits (if you are Star Gold with a partner like Aegean). At the very least, it can make your airport process a bit longer and could cost you more money if you are having to check excess baggage.
If you already have travel booked that will include US Airway flights and it really matters to you to receive those benefits, you can always pay the change fee to change your award ticket (it will cost $75 per passenger if your travel is more than 21 days out, $100 if travel is within 21 days, if ticketed with United).