Actually, the end result depends largely on the texture in case. Some types of textures convert surprizingly readily to a normal map with CrazyBump, some... not so much. Textures where there are clear seam lines visible, usually work out well. But CrazyBump reads all great enough contrast changes as changes in elevation, so if there are any patterns painted in the texture, that's gonna show in the normal map and not in a good way very likely.
None of the normal maps generated from colour texture by CrazyBump beat the end result from custom handcrafted normal map from an experienced texture artist, though, but as a makeshift solution for us poor peons waiting for the normal maps to appear in MediaVP's, CrazyBump can make some models look surprizingly good with the minimum amount of work and time invested.
I wouldn't put them directly to MediaVP's, but for some ships, crazybumping the texture actually works. For example this ain't too shabby - there's an ugly seam in the middle, the surface detail is a bit overshot and the detail is not on par with what a specially crafted elevation map would produce, but as a whole, I daresay I rather pick this normal map than none at all.
