I have the compact (50/34) and both 11-28 and 12-25. I used the 12-25 on a hilly race a few weeks back. The 28 would have been extremely useful on those hills 20%+ grades.
Next year I will switch to the 11-28 for that race and probably use the 12-25 for pretty much everything else. The 12 vs 11 isn't an issue since I never needed that gearing. On the descent I was able to reach 43mph without even pedaling.