I was a huge fan of the dk1 when I first got it, then I got the dk2 and

'ed at the stupid amount of cables required to set it up. I would bring the dk1 to parties, people LOVE that shit and it was so simple to set up. I would just bring my small laptop and thats it.
I think I took out my dk2 maybe 5 times total. It was a total nightmare to setup, and troubleshoot. I didnt even bother with the final version. You have to set up a bunch of cables, a fucking webcam on top of your laptop, you need a pretty damn powerful laptop rig to ensure 90fps.. it took the fun out of it. Of course, its much better with the final version, but after owning a dk1 and later a dk2 for almost two years, VR feels a bit old already.
When I brought it at social events, people love the fuck out of it. They loved the 'on-rail' demos, and no matter what, they always asked about porn stuff

, which always got the big reactions (

) and brought out the laughs. I had two videos demos, one with a pg13 stripper entering 'your apartment' and dancing around you while getting undress. Guys would get all silent and intense when viewing that one with the helmet, it was hilarious
The other video was a fmm threesome featuring the viewer as the girl fooling around with a sweaty latino guy and a black guy with a giant dick. Women would laugh non-stop during that one and joke about this 'being their first time with a black guy'. We did get one girl who tried it and completely hated it, saying it felt wrong and it made her feel like she had cheated on her boyfriend.

But yeah, overall, people really wanted a kit, but it was too expensive and too complicated to setup for them
I think some sort of simple integration with cell phones is the way to make it mainstream for the average person.