This is probably too late to address the potential purchaser, but I don't know of anything as good as the Kagayaki CarboNext for the same money. It's very similar to the Kikouichi line (they were once OEM'ed by the same company). I have an Ichimonji TKC and a CarboNext of the same size and despite being just over 2/3 the price, the CN actually exhibits better F'n'F. Both seem to take and hold an edge equally well and the (well founded) rumor is they're the same steel & the same blade with slightly different finish (different brands use a different bolster, for example).
The CN really does behave like carbon steel on the stones. It takes a screaming edge and sharpens up very easily. It can be made to patina but I've never seen any rust so far. This is just one guys experience but all the CN's I've seen were pretty well ground. I personally have two of them, a 240mm gyuto and a 300mm suji. Both were pretty much perfect. A friend from another forum also purchased three of them (120mm petty, 210mm gyuto & 300mm suji) and had them shipped directly to me to sharpen and send to him. They too were perfect.
One word, though- they have a pretty poor factory edge. Only one of the five was acceptably sharp to me. That's really not a big deal since I almost always wind up sharpening a new knife before I use it but it might be to you. And the folks I've spoken to that bought the "Extra Sharpness" option said they were very disappointed.
But once you get it sharp it's all to good. Great edge retention and a screaming edge off the stones. And if it matters to you they go with Japanese natural stones like PB goes with J.