westfw:
Is 1.0.x obsolete, or does it still have useful features on its side?
Well, 1.0.x is called stable, and 1.5.x is called beta, so the status of a recommended stable release that 1.0.x has on it's side. I cannot evaluate the program if this really is the case, but it is a significant thing. I wouldn't want to think that of the two versions one if unstable beta and the other one is obsolete (well there is also the fork for the new Intel x86 -thing). Maybe i'm just oldfashioned, but typically software has a stable release plus possibly multiple development branches.
Does anyone have a clue when the 1.5.x might possibly acquire stable state? I know Arduino is expanding and growing, and that's awesome 
The 1.0.x -serie has been getting updates as well, but at some point i would assume it would be a good idea to start thinking of the 1.5.x as the recommended one, what do you think?