I got mine yesterday as well. For those still uncertain, I can confirm it uses Band 17 MBS LTE (as deployed by AT&T, Rogers, Telus, and Bell), not Band 12 MBS LTE as deployed by T-Mobile.
Dual-SIM support surprised me. As I expected, if you are talking on the phone the other SIM is totally locked out. But I went to Youtube and started streaming a video, then called the other SIM, and the call went through on each of several attempts. And yes, I remembered to disable WiFi first.
This pleasantly surprised me. I suppose it's because it's packet data, so it can poll the other SIM between packets. That makes dual-standy much more useful than I expected, as I had feared data use on one would make it impossible to receive calls on the other SIM, and I'm happy to be proven wrong.
Mind you, voice worked fine in either SIM slot (though only one SIM at a time obviously) but I was unable to get data to work in the second SIM slot no matter what I did. I'm not sure if I made a rookie mistake, but I couldn't get data to work in the second SIM slot (not even over Edge). I'm really uncertain whether the second SIM slot is 3G or 2G. With two SIMs in there, it lists one as "LTE" and the other as "G". I'm concerned that means GSM, eg. 2G. The second SIM slot was only 2G on the original Blu Win HD, and this is a budget phone so corners have to be cut here and there to hit the price point they've aimed at. If that's the case, then the second SIM slot is useless in Canada on every network other than Rogers' network. Only the Rogers network has 2G GSM, the other carriers all started their modern networks with HSPA and have no 2G GSM at all.
Hopefully this second SIM slot supports HSPA, as this phone seems to have been made with Canada in mind with its frequency support. I kid you not. Consider, that it supports:
3G over 850MHz and PCS (as deployed by the Big Three, and the traditional regionalsl)
3G over AWS (as deployed by Wind and the other new entrants)
LTE over AWS and Band 17 (as deployed by the Big Three)
LTE over BRS (AKA band 7) (as deployed by Rogers and Bell)
That's every major frequency deployed in Canada. None are missing.* And none are added aside from the European frequencies you typically get in every halfways-decent phone for roaming purposes (900 and 1800MHz 2G, and 2100MHz 3G).
There's no U.S. carrier that supports band 7 (Sprint has the spectrum and, as usual, rolled it out as exotic band, band 41 in this case), so that's useless in the U.S., but hugely useful in Canada where Rogers and Bell have rolled it out, and Telus and other carriers likely soon will roll out more band 7 spectrum. The auction to dole out the rest of the BRS 2600MHz spectrum is happening in Canada as we speak (results expected to be announced any day now). Instead of band 7, you'd probably want band 2 (PCS LTE) in the U.S. which is used by AT&T, T-Mobile, and a few others.
If I were designing a phone for Canadian carriers, these are exactly the frequencies I would want it to have. If I were designing it with Americans in mind, I'd make some changes: if I were aiming AT&T I'd support bands 2, 4, and 17; if I were aiming T-Mobile I'd support do the same, except I'd swap out band 17 for band 12. And yet Canada is a very small market for unlocked phones, as we're so tied into the getting subsidized phones on contract here. Very curious.
* For the purposes of this discussion I'm ignoring Telus' recent refarming of their (now) tiny slices of CDMA2000 spectrum into equally tiny slices of LTE over band 2 and band 5. As far as I can tell Telus is doing it "just 'cause" because they're doing it in areas that they've already rolled out band 4 and 17, so it offers neither coverage, nor (significant) capacity advantages over their existing network.