I'm planning my next tour. I'm considering best of Europe (21 days) versus Greece (14 days). Although it's highly subjective, I'm curious for those who've taken both which was your favorite. Also, I'm always willing to broaden my perspective, so if not one of these, which tour was your favorite. Finally, why you most feel that way. For example, as I consider my experiences, I realize the reason an experience often mad an impact was due to its setting, (natural, historical, cultural, intellectual). Then due to a comparison within that setting, (rarity, beauty, size, variety).
Why don't you review the scrapbooks and Trip Reports here on the Forum? That research should give you great feedback on the daily activities of each adventure. There are no bad decisions here. Good luck!
https://www.ricksteves.com/tours/scrapbooks/tour-alum-scrapbooks
I agree with Pat and you might also consider the time of year, if weather is a factor, as Greece can become quite hot during the summer months.
Our 14 day RS Greece tour in 2024 started the last week of September and we stayed through October 13. It was still warm every day in each location - 75 to low 80's and relentless sun. We had 5 minutes of rain in Nafplio while eating under a restaurant's canopy. It was a tad too warm sometimes for my partner and I had to slather 50 SPF quite often. In retrospect it was nearly perfect actually.
I did the 21 Day Best of Europe when I was getting back into International travel. I'd retired from my career then did 2 years of parent care. During the tough times I 'd take the RS tour catalog out on Mom and Dad's back deck and flip thru pages. I decided when I no longer had responsibilities I'd do every tour that was of interest to me, lol, starting with the 21 Day Best of Europe. What a great decision! This tour was everything I wanted it to be and more. I really enjoyed my tour mates with whom you have a special bond since this tour is long, loved my guide, and loved everything I saw.
I started in London for 4-5 nights, then took the train to Amsterdam and went out to Haarlem 2 nights before the tour started. At the end I did a back to back with the Best of Paris week-long tour, followed by another week in Paris with a friend.
I have not done Greece.
I'd say pick whichever one sounds like more fun to you. There is a good balance of city, smaller towns and outdoor locations (Cinque Terre and Switzerland) on the 21 day tour.
Here is a recent discussion on favorite RS tours