Having seen the video again tonight, I am thinking if 1700 would overclock to 4.2 with the Taichi or better get the 1800X.
Many have OC the 1700 @ 4.1 with lesser boards....
Well it's really down to price to performance, and the main issue still seems to be early BIOSs.
If I was buying right now, I'd rather save €170 and get the 1700 then run at 4.1Ghz ( with chance of 4.2) compared to the 1800X for a chance at 4.2Ghz.