How does it compare with Crystal cruises or Regent, I wonder?

Lots of swingers but they are not aggressive about it. Just if they are wearing anything with a pineapple on it, or you see such a sticker on their door, beware.

Not to be confused with people wearing watermelons on their clothes -- that's people who are pro-Palestinian.

We're also in our 50s and have done Viking Ocean the last two summers. Plenty of people our age and even younger (honeymooners, multi-generational trips, etc.) We took our two sons in their 20s last year.

Reach out to Pavlus, which rebates a large amount of their commissions to their customers. You'll pay more if booking directly with the cruise line. Another agency to consider is Vacations To Go, which also provides significant discounts.

https://pavlus.com/

https://www.vacationstogo.com/

Consider checking prices with Costco Travel, too.

My parents have been on many throughout their 70s and love it. They use a travel agent and love that too--for example they are going on one out of Greenland and the travel agent handles the flights bc of the lack of days where there are flights to the US (Viking may even charter a plane for the whole cruise to get back to the US, but my parents don't have to worry about any of the details). I don't know their travel agent.
They usually do the included tour in each port, occasionally paying for different excursions. Included wine with dinner is also a favorite (aren't big drinkers so that is perfect for them).

We are considering a Viking Cruise on the Mediterranean and not sure whether it makes sense to use a travel agent or book direct. Does anyone have firsthand experience? Also, if anyone has a travel agent who specializes in this, recommendations would be appreciated. And yes, I know, Viking skews old. But we're pushing 60 and want a relaxing experience.