Based on what I see from the development blogs, I see that most of the effort is just fighting against the huge complexity of building an O/S, more than the qui

Based on what I see from the development blogs, I see that most of the effort is just fighting against the huge complexity of building an O/S, more than the quirks/bugs of Windows itself. You can see very often the pattern of "X was implemented using the library from Y, which works but not well" or "Y was implemented and working for Z case, but it's effectively broken" and so on. I've seen comparatively little complaints of the kind "bl00dy Windows performs this functionality in an awkard and messy way". I don't really have much faith in ReactOS, although I would really love to see it mature. Following its evolution with the time, I can see clearly that it's a type of product which is doomed to be "90% functional" for its entire life (unless somebody will throw a massive amount of money at it). While you could consider Wine to have the same fate, there is a distinction in the fact that Wine is more directed to a per-case basis, which makes the "90% functionality" state acceptable.