I noticed a confusing trend recently which makes it difficult (at least in my opinion) to judge the quality of a software prerelease version. A recent example is SL5. Whereas SL5 itself had the well-known labels of "Beta" and "RC", the corresponding Blend version is labeled "Preview for Silverlight 5". What does that mean? Is it Preview < Beta < RC, or Beta < Preview < RC in terms of quality? And what about CTP? Is it the same as Preview? Why not return to the well-known Beta x, RC x, RTW labeling?

Can someone shed a light on this?