I don't get the excitement over a card that performance wise is roughly equivalent to a 1060, but with only a 3 month warranty and virtually zero resale value. Sounds like a pretty terrible deal to me.
A 1060 does between 18 to 23 mhash.
If you OC alot you could get more but that is not stable with 6+ cards.
This 1060 is cheaper and does 30mhash out of the box!
What is there not to like?
the 1080 version does 60mhash!
The 60 mh/s quotes for the P104-100 are VERY unlikely to be lived up to or prove to be close to accurate.
The GTX 1080 that card is based on doesn't even manage 30 Mh/s (more commonly 24-26 ballpark), as the GDDR 5x memory it uses has seriously worse latency than GDDR 5 as used in the 1070 (which only manages right around 30 Mh/s in most cases, rarely as high as 32 if you get lucky in the silicon sweepstakes on you memory ability to overclock lots).
Even the GTX 1080ti with a TON more cores than the 1080 only manages mid-30s ballpark.
I flat out do NOT believe the P104-100 will be capable of even 40 Mh/s on ETH, and would be amazed if it managed 45 - even if it moved to GDDR 5 instead of 5X it's STILL not likely to manage 40.
On the other hand, nobody sane tries to mine ETH on a GTX 1080 or GTX 1080ti - they mine ZEC and it's derivatives, skein-based coins, groetsl-based coins, libr and derivatives, and such.
The P104-100 should be very nice for mining THOSE coins.
The one BIG advantage of these cards will be power efficiency - no video circuitry, the video-specific parts of the GPU chip probably disabled either on the chip or in the BIOS (similar to what TheStilt did with his line of R9 290(x) modded BIOS from Litecoin mining days that reduced the power draw on those cards a LOT), I suspect that the minining-specific versions will see 20-30% less power draw at the same clocks vs the consumer versions.
They may gain SOME hashrate via BIOS mods to improve memory latency (AKA "strapping" as used on the RX series), but I suspect those gains will be less than 20% and might not manage 10%.
None of the rumors I've seen so far mention HIS or PowerColor, but I would not be shocked if one or both of those jump on this bandwagon.