The pictures from the E-1 uprezzes quite well; from what I know and heard, it starts to get slightly pixellated from A2 and larger (but yet to try it myself!).
But I definitely know that it prints on A3 great!
Well, as far as cams go, it doesn't need to be new to produce quality pictures. Sure it may be run slower than the new ones, but it is built properly; it feels like something you could keep for years. The new cams nowadays feel "disposable".
Another thing I have to add is that the 100% viewfinder on the E-1 is addictive; it aids composition to a very large degree. With it I can frame the shot exactly the way I want it.
With the E-300, distractions stray into the edge of the picture sometimes.