Hello! I literally just booked one last pre-devaluation flight with Avios. My husband and I both got the card when they were offering 100k miles each a few years back and man have we gotten our money's worth! My husband is in Nashville now at the NHL all star game and while he's paying OOP for the hotel, he's getting breakfast and lounge access tonight free due to his Gold status with Marriott courtesy of the Ritz Carlton credit card!
I used the Companion pass last August to take my daughter (12) to London and Scotland (the add on to Edinburgh was 'free' because of the routing rules). As you know, you still have to pay the ridic BA fees bc the flights have to be on BA metal; that being said, we flew business class there (upper deck, great experience) and in first on the way back (Concorde room and all that) for 100k miles and less than $1800 in taxes. We used Marriott points for 5 nights at the County Hall Marriott (unbelievable location) and Hilton points for the hotel in Edinburgh, so I think I did pretty well all things considered! Love travelling for pennies on the dollar!
Out of pocket would have been over $2300 in economy and over $4300 in first! We have the Marriott card but not the Ritz Carlton. I may have to look into the benefits of that one. We've been using mostly the Club Carlson card for hotel stays in Europe since they give you 40K anniversary points each year. We stayed at the Radisson Blu in Edinburgh for 3 nights on points and saved over $1000 and we've got 2 nights booked in Dublin this year on points saving well over $800. $75 annual fee and totally worth keeping the card. I really need to brush up on understanding routing rules. I've likely blown through miles I didn't have to. Then again, I barely know what I'm doing here. So far it's working though 
Love doing the travel hacking thing. Best. Hobby. Ever.
