I’m always hesitant to buy miles and points. Airlines and hotels are profit-seeking entities; they wouldn’t sell the miles and points without some chance of making a profit on them. As a testament to this, I have a hockey puck sitting my closet from the AAdvantage/Verizon snafu, just waiting to be returned as part of whatever settlement of miles I might get.
Before handing wads of cash to US Airways and its partners, it’s worth figuring out the value of a mile. US Airways has an award chart for itself and for its Star Alliance partners. An off-peak (1/15-2/28) award to Europe runs 35k miles in coach and 60k in business. A quick check of availability shows that there actually are some awards to Europe available for that little, even around President’s Day weekend out of Philadelphia. If I value a trip to Europe (in the dead of winter) at about $550, this amounts to about 1.57pm. Availability next summer on US for the lower tiers of awards looks minimal, so its hard to point to a hypothetical trip to the summer and compare it to a $1k revenue fare.
US also has a Star Alliance award chart. US isn’t quite as generous with awards as UA/CO. There’s a limit of one stopover at a Star Alliance hub or an open jaw. The Points Guy and FlyerTalk both have guides to maximizing these awards. Hong Kong and Japan fall into North Asia for 120k miles in first; UA puts Hong Kong in South Asia (140k miles) and Japan by itself (135k miles).
US currently has a promotion through September 15, 2011 offering a 100% bonus on purchased miles. 100k miles can be purchased for 1.478cpm.