Interesting to see it listed under the Laptop DTRs too. Suggests it's a straight swap which would be interesting to see how it operates at 4.5ghz in the chassis.
Would be silly to get a Kaby Lake build when Zen is still largely unknown and we don't know quite how good it will be. Kaby Lake seems to be very disappointing. Clock for clock there seems to be almost zero improvement in most benchmarks.
Zen is still a little while away, and while it's a bit unknown it doesn't seem like it will sink Kaby Lake in terms of performance, since what we have seen of it - granted from an earlier sample - is a similar IPC to broadwell. This seems to be the expectation that AMD are happy for the rumour mill to keep going with (notwithstanding AMD's generally terrible marketing...).
If one doesn't really need a PC now it may be worth waiting for Zen to deliver a more cost effective option (very similar performance somewhat cheaper), but it's not like there's any indication people buying a Kaby Lake PC are going to regret it.
I suggested people wait a couple weeks for Kaby for the slight increase to performance and the extra feature sets of the new mobos, but won't generally suggest they hold out a few months for Zen. Though when Zen's closer I probably would.