The quality of the components is great. Machining is accurate and everything fits perfectly. The engine runs really well at low speed and will self start most of the time.
My kit had 2 minor problems;
1: The siphon tube leaked steam under pressure, that was a simple enough fix with a propane torch and soft solder. If you aren't sure what you're doing with that repair I'd suggest you reach out to support via email and they will take care of the issue.
2: The included hardware is where the kit is let down. Many of the smaller screws (M2x5mm specifically) in my kit were malformed and could not be properly tightened with the included wrench or any of the tools I own. The socket in the head and head itself appeared to me misshapen. This is a really minor problem that can be caught during assembly and addressed then.
Overall I am very happy with the kit and impressed by the support from Enginediyshop.