I don't like either MP Starscream toys. The second one is better than the first but the experience with him told me I did not want to buy it five more times in different colours and wing configurations. A superior new Starscream might convince me to buy a Thundercracker and/or Skywarp repaint - although I might keep the current Starscream.

As for Optimus, I like both so far. MP01 was extremly remarkable toy of it's time and is still very well designed. MP10 though is great in may ways. If a new one was pretty good I'd definitely consider it too.