Well. my kit arrived yesterday and after going over everything in detail, I decided the first one would be like Dmitry's - the early early with the Watts prop. I'm doing K9795, the very early 19 Squadron airplane with the yellow-surround insignia in all positions.
I started work on the kit today, doing it on breaks from working on the current manuscript (thank you thank you Mr. Schmuckerberg for the screw-up that locked me out of @#$%$#@! FleeceBlock and threw B'rer Rabbit into the briar patch, I now have plenty of time to keep up the work on the book and also work on a model) and as of this evening it is fully assembled and ready to start painting tomorrow. There were no difficulties encountered. The exhaust had the short-shot glitch, easily solved with a bit of C-A glue and a sanding stick. No other molding glitches on the kit.
The only "glitch" is that those gun barrels you put in the wing should be attached at their rear with C-A glue to prevent capillary action with liquid glue screwing up the look of the gun ports, but that's more a MIP (modeler-induced problem) than any problem with the kit.
Overall my experience parallels what Dmitry has reported. If you have familiarity with the earlier Eduard Spitfire kits, you will have no difficulty here. Just be certain to pick what your end result is going to be at the outset and pay close attention to the assembly callouts that are for your specific choice, because there are a lot of those.
Overall, you're not going to want to throw out your Tamiya or Airfix Spitfire Is, but after doing one of these you're not going to want to buy any more of the others if you're a Spit boffin and want accuracy and good research. None of the things that made me say "Dagnabbit!" while doing the Tamiya Spitfire are to be found with this kit.
The surface detail is so close to real that at a distance of about 5-6 inches in daylight light, you can only see the rivet detail if light is playing on the surface. Guess what, from about 20 feet away with a real one, the effect is the same! The surface detail is just stunning - petite and accurate.
Overall, the kit lives up to the hype, the result if you take your time and study the instructions will be a stunner. It's definitely The Best Spitfire I In Any Scale.
And I think I will be trying that "marbling" preshading on this.
Oh, and Dmitry - don't worry about your "Dark Earth" color. According to the research Fundekals did on Spitfire Is for their great decal sheets, there wasn't an "exact" shade of Dark Earth during Spitfire I production. One little thing I didn't know before doing the Tamiya Spitfire using the Fundekals is that the airplanes were painted in a "smooth" finish, not a flat finish as later marks were. It should be a semi-matt "satin" on the final finish.
One other thing that was "new news" to me in the Fundekal research is that on the black/white undersides, the entire landing gear - inside/outside the door, the gear leg, gear well, etc., was the surrounding color. And when those airplanes were repainted sky underneath, the black/white on the interior door, gear leg and well was left unpainted.