Not real LEGO. Not their own designs.
Turns out this website is not selling genuine LEGO bricks, but cheap Chinese imitation bricks (they call it "LEGO compatible" bricks). Also most of their designs are not their own, but designs that can also be found at websites as rebrickable.
After an inquiry about a set, it turned out the actual instructions were not included, but had to be purchased separately from the original designer.
After a bit of research, I managed to get the imitation bricks quite a lot cheaper than when I would buy them from Vonado.
So conclusion: if you want REAL Lego bricks, Vonado is not the way to go. If you just want an easy way to get the Chinese bricks for a certain set and you don't mind paying more than when you would source them yourself, than you can consider Vonado.
I only give one star because they are absolutely not clear about the fact that the bricks they sell are not LEGO, but imitation bricks. I almost bought a set there thinking this was real LEGO, but the price made me suspicious. Good that I did some more research and contacted them, otherwise I would have been quite disappointed...
UPDATE:
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Wow, just a few days after my negative review, 2 positive ones pop up out of the blue! Both by Trustpilot members who never placed one single review before. Coincidence? Nah, I don't think so. Nice try, vonado_bricks, but a bit too obvious!
November 30, 2020
Unprompted review