I have 5930K plus a dual cpu rig running 14 Core Xeons so can't really justify the £1400 price tag for a ten core, which is more than I paid for two xeons (Engineer Samples though).
I do some video editing but never felt I needed to upgrade, but I do a lot of BONIC computational stuff also.
This is one of the problems with the pricing of the 10 core, having the work for a 10 core to do. To justify the price. I think they are trying to get the money in asap due to the limited time they have before the new skylake- x hits retail.