I kind of agree with Trjp, 20% is alot.
Imagine switching to GLES2 means a single customer didnt buy your game?
What if ten couldn't buy your game?
What if fifty potential users couldn't buy your game?
I believe GLES2 is the future and in a year this entire discussion will be irrelevant, but for the time being it is relevant.
I'm not happy with the fact support for the GLES1 branch has been dropped overnight. Since there are still some memory management issues. Then again, Nicholas isn't being paid to maintain GLES 1 so we're at his whim. The issues are too complex to solve myself, so fixing it isn't an option.
The downside of any opensource project IMO.
Also, I'm not trying to pull anyone down here. I'm thankful AndEngine is here today as it is. I'm simply elaborating my point of view on the matter.