I built the SE kit. Also, I bought a stepped attenuator recommended by Kevin. In this way I have been able to run the phono peamp directly into my tube monoblocks. I like the K&K phono preamp very much. For less than $1750 (delivered, including attenuator) plus assembly time, I got an excellent phono preamp. I've used it with a Michell Gyro SE and, now, with a VPI Aries II. These two tables are quite different design and sound. The K & K works well with both of them. I use a Dynavector Karat 17D2 MK2, a low compliance moving coil cartridge.
The kit quality is excellent. Kevin will give you good support if you decide to build it yourself. Based on my experience with Kevin, I am confident that the factory built unit will be excellent.
Please expect the Lundahl transformers to take a couple of hundred hours to break in. Once they do, the sound will have lots of air and detail.