I was about to lose united miles since I had not used that account in a while. I have five other airline accounts. Being SPG platinum, there is no minimum miles transfer cap (I think it is like 2500 for a base member), so I transferred 10 SPG to 5 UA to preserve the account. No way that 2 SPG --> 1 UA is a good deal, but to salvage an account it is worth it. Also, it completes within two weeks (usually faster).

Many of those mileage shopping partners tend to take a long time and sometimes do not even post without a fight. I would only use one of those if I had time to look for an alternative should they not post.