I would just share our experience as I had promised. We went to the UK and my husband only needed to show his passport and residence card. He didn't get any stamp at all in his passport. We live in Spain, I'm a Swedish (EU) citizen and he is a non-EU citizen. He have a article 10 residence card from Spain.
As I have mentioned in my main post. We traveled from Sweden to the UK and then back to Sweden from UK. There was a little problem at Sweden's airport. First of all, we had to go to the Ryanairs visa control desk. The girl who stood there had never seen a similar residence card, she said. She called someone else. We explained to them how it's work. The problem was that they could not find the text "family member of EU citizens" on my husband's residence card because this text are in Spanish on the back side of the card. They called a few calls and it took a few minutes before they realized he hold a article 10 residence card and he didn't need a visa.
After the Ryanair visa check, we had to pass passport control and that was the same problem there. We had to stand for a few minutes and explain to the immigration officer. He said that everything is in Spanish on this card and he could not find the text "family member of EU citizens" on it. But I showed him the text in Spanish on the back side of the card. I told him that we have a marriage certificate and proof of our address in Spain if he wish to see them, but he was uninterested. The fun in all is that we have the same last name and they can see directly that we are married.
The officer took my passport, my husband's passport and residence card and went to another office. We had to sit and wait a few minutes. And at last he came back and said that is okay and we are allowed to go.
That was the same problem when we came back from UK to Sweden. On the passport control they didn't know anything about the residence card and it took time before they let us in. I strongly advise you to travel from and to the country which issued the residence card. In our case we would fly from Spain to UK and then back to Spain.
Unfortunately the Spanish authority issue the residence card only with Spanish text.
In the UK they said nothing about his residence card at all. They checked my passport, my husband's passport and residence card and then the officer said "welcome to the UK".
I believe in UK they know about all residence cards issued in different EU countries and they didn't know that in Sweden. I just want to add that this experience is from a small airport in Sweden. If we had traveled from one of the big airports in Sweden maybe they would handle it better and had knowledge about the residence card.