I had exactly the same thought, after much research figured the "best" to get is the Samsung, not available so went for the second best, the Dell.
Display res is 1440x1440 per eye, less than Sammy (1440x1600) but has the same 110 degree FoV (next is Lenovo with 105 then the rest at 95).
Now the reason to go for the Dell (or Sammy if you want to import) over the others is simple, requirements. I run a not very beefy system, i5 4430, gtx970 and 16Gb RAM, less than the minimum specs for the Vive, with the Dell I can rank up settings to "omg, thats nice looking" and still have nice frame rates.
The obvious disclaimer here is that I've never tried the Vive or Rift on my PC so have no idea if my performance would be the same or better/worse. Vive/Rift games also work on the WMR, I'm spending many, many, many hours playing ETS2, also ED.
I think the main issue is that they are marketing it as a mixed reality device, who the hell knows what that means? It also isn't, it's just VR so if they marketed it as a VR device needing a less powerful PC then they may have got somewhere, also most of the early adopters have already adopted so it could quite well be that VR is at market saturation currently? of course, should MS let the WMR headsets slot into an XBONE then they will sell "a lot".