urk .... i would consider an option to a 1600/1600X only if it was a 8600K, since i would come from a 6600K tho for the price i would prefer to have 6C/12T instead of 6C/6T
and changing mobo for changing mobo .... i rather go with the one that would support the next refresh
But yeah the i5 8400 is a beast, and it's a wee bit cheaper than the 1600.
beast ... are overrated (the use of the term "is a beast", is ) price consistency is also overrated .... the 8400 is as much as a 1600X where i live .... the 8600K is bound to be close to a 1700X and the 1600 is "the best budget CPU offering 6core and SMT"
tho if the 8400 was a "wee bit" (3€? really? well that's the price difference i see atm outside Switzerland) cheaper for me too ... i would still go for the 1600 because 6C/12T and 16mb vs 9mb (even if HT/SMT are not really that useful ) and same TDP (or 1600X since 30w more is not that big ... that was rather what i expected for the 1600 alone .... since my 6600K is a 95w )
as far as looking benchmark .... i don't like biiiig result panel that make a 0.1-5-10fps difference seems worlds apart
ofc if i had to choose between a 8600K and a 8400 ... i would go 8400, not much difference for the overprice
but for the moment i would go AMD for the sake of supporting them (ok not GPU wise tho ... but for CPU they did a real good coming back even against CL that came after) and also because, even if my main domain is gaming ... i never know when i could fall into Ryzen's predilection domain (Rendering streaming encoding, etc etc etc )