Back when Intel launched their SSD 750 Series product line, their hope was that the motherboard industry would adopt the U.2 PCIe connector and add those ports to all motherboards. Well, it's over a year later, and we've only seen U.2 appear on a very small fraction of currently shipping motherboards. It's far more likely to see motherboard manufacturers simply tossing in a U.2 to M.2 adapter than to incorporate both onto the board itself. Since things have panned out the way that they have, Intel has recently let us know they will be introducing a new SKU of the SSD 750 products:
Instead of the bundled U.2 cable (seen above next to an ASUS Hyper Kit), the alternate will include a U.2 to M.2 cable, eliminating the need for an adapter for consumers who have no native U.2 port on their systems.
For now, the only available products on the market have the U.2 cable, so don't worry about getting the wrong one. Once the new SKU hits the to market, we should see product descriptions indicating which cable is included. Those purchasing starting this summer should be aware that in the future there will be an additional product with the alternate cable, and be careful to purchase the desired product/cable.