Wow, I thought they were the same price. I'm sure they are making up for years of not raising the price and a new model change is the way to do it, even if the costs are not high for the change (and certainly those tiny changes cost them next to nothing). I'm not saying they are taking advantage, I've been wondering when they were going to raise the price on these, even without changes.
My guess is that they sound very similar, and that the main difference in sound is the diaphragm - if you can even hear a difference. I suspect the availability of two models is temporary until parts and built units of the SE are exhausted. I'm not a bit concerned about getting rid of or updating my SEs. Now, if there were major horn geometry changes, a fundamental change in the cabinet, or if there were a change from foam surround to pleated (obviously not the case, it was already pleated) I would be exceedingly curious to hear the new ones. As it is, no concern, I love mine as they are.
If you have plenty of money and don't care much about the $10k, get the latest and resale will be higher. If the money is really meaningful get the SE before they are gone (or at least find out if they are going to keep making it, which does not make a lot of sense to me but might be true).