I assume your a Haswell owner threatened by Skylake? Nothing else makes sense - for something buying new of course they'd be best off going z170/Skylake:
1. Upgrade path (Haswell = dead socket)
2. DDR4 (3000Mhz kits are cheap, and faster speeds available all the time)
3. 20 more PCI-E v3 lanes from the chipset for use with high speed SSD's
4. Much more consistent overclocks (as confirmed by 8pack who tested loads of these), 4.6-4.8Ghz is very common.
5. Cooler running CPU, thanks to 14nm process
6. Yes it's more expensive - though did you expect it to be cheaper than the 'old stuff'? Shop around, it's only a £30-£40 premium.
7. Faster performance, significantly so in several applications, gaming 2-5% faster.
Hehe, nope, I'm on 2500k, not threatened at all why would I be? There has been nearly bugger all improvement since sandy bridge. I class all the processors after that in the same group, benchmarks are all within around 10/15fps gaming anyway.
1, like I said who upgrades the socket anyway, by the time you need to replace the cpu it will be oem and cost more than it is worth anyway. Might as well buy the best CPU you can at the time.
2, who cares about ddr4 or fast ramspeed unless you are on an integrated GPU, so few gains
3, high speed ssds so someone on a 1200MB/s drive will boot into windows in 4 seconds compared to my 550MB/s drive that does it in 8 seconds, again who cares.
4. Can't argue with the overclocking apart from you need to buy a good cooler since the skylake k processors don't come with one at all so add some money to the build.
5. Fair enough can't beat a die shrink.
6. Last time I looked there was a massive premium on these new chips looking at +100 quid plus cooler if getting the k chip.
7. 2 to 5 percent is not significant, the extra 100 quid into GPU would net more than that. Fair enough if they are using it for other applications.
8. I put way to much effort into this lol.
If you can get the newer tech for 40 quid more go for it but I bet it's not in stock where you have seen it and 40 quid more into a gpu would still get you better performance increase.