Build time is only a couple of hours with no pitfalls I could detect. Just the backplane and processor board is enough to bring up a system in one of the operating environments hosted by ROMWBW. Add a storage card for the fully operational system.
The 5-slot backplane is fine for people who want to expand to a custom system, otherwise I would recommend a 3-slot backplane from Stephen Cousins for the smallest footprint.
Documentation covers all you need. Dealing with Karl is a pleasure, he is responsive and helpful. Posten Norge provide very efficient shipping.
The black PBCs are very good quality and look cool! All the required components supplied and documentation fairly clear. This is probably not a beginners kit, but it's not difficult if you are confident soldering and can read the schematic. Recommended.