Both the SA-8 and E8 v.2 are much more advanced in terms of reliability, power handling, and build quality compared to the E8 v.1 -- I am alot more familiar with the capability of my build house and what they can and cannot do well. So there are almost no QC failures anymore (on the SA-12s I've had 0.4% not pass QC... yes zero point 4 percent).
I am also more familiar with what people will do to products regardless of how I rate them -- so the new products are designed to handle WAY more abuse... I cannot imagine anyone being able to cause ANY damage to either the SA-8 or E8 v.2 will full rated power down to 20 Hz even free-air. See the E8 v.2 video... that was a 1500D @ 1 ohm at a fairly high volume level with frequency sweeps dipping down to nearly 20 Hz! With a rating of 200 RMS *nobody* should break one.
As for the two current eights... the SA-8 and E8 v.2 -- both are great little drivers. Pick whichever one fits your power / depth needs.