Also a consideration is your home airport. If most of your flying has its origin at a hub airport like mine does (Chicago), then making the effort to bump up to 1K from Platinum might well be worth it if UDU's are important to you, especially if you buy discount lower fares (i.e. K, L, G, S, T) like I do instead of higher priced fares more typically purchased by business travelers (i.e V and above).

As a Platinum based in Chicago traveling on discount fares, I am lucky to get upgraded 10% of the time thru UDU when flying between Chicago and a major market, and perhaps a bit more often for lesser markets. I can only guess my percentage would improve as a 1K because I would move ahead of nearly all Platinums for UDU, even with the discount fares I normally buy. That's why I am taking 27K of MR's this month to get to 1K as soon as possible and enjoy it all the way into early 2014. For me, it's worth a try to see what happens!