So I heard the E70 and E40 again. This time around I was much more impressed by the E70. For some reason, this E70 sounded quite different to the one I heard at Canjam. This E70 was more impressive - it had incredible bass extension and impact. The bass was visceral, powerful and fun - yet extremely controlled with no hint of bloat. I have never heard bass this good coming from a BA driver. And while the bass was strong, it did not overpower the mids, which were relatively uncolored with a pinch of warmth and still had amazing detail and transparency. It did not possess the AT house signature here, instead going for a neutral/reference tuning that's not analytical. The sound as a whole was extremely coherent, refined and musical. It might be the most well-tuned Audio Technica IEM I've ever heard, worthy of the reference moniker.
As for the E40, when I heard it again I did find some deficiencies compared to the higher-end CKR models. The E40 was slightly less refined, and the highs were a little grainier, maybe harsher. It also had a slightly smaller soundstage compared to CKR9/LTD. However, it did not lose to the CKRs in terms of dynamics, speed and musicality. It had more forwardness than all the CKRs, perfect if you want unrestrained intimacy. Still an immensely enjoyable listen and a perfect gateway to the Push-Pull driver sound. Don't let its small shortcomings to the CKRs discourage you; for the price it is an incredible bargain and unmatched for what it offers.