Out of the 13 Echo Star discs I have 4 have started out less stable than regular Star (2 Presidents Cup Katanas, 2 yellow Destroyers) 1 has started out about the same as regular star (green Destroyer) and 8 have started out more stable (4 orange ES-DD2s aren't that dramatically more overstable, though very noticeably so, 3 green ES-DD2s and a yellow Teebird are much more overstable than regular). Out of those the Presidents Cup Katanas and the Teebird are super freaky domey, the Destroyers are poppy, the orange DD2s are regular domed and the green DD2s are very flat.
A small sample obviously, but if you want to take something out it it's that E* tends to be domey and more overstable, but overall it can be anything.