Viking is a great option for people who are worried about planning their "grand European vacation". My mom and I went as a college graduation gift, and it was our first time traveling away from the East Coast. Viking made scheduling the flights and transportation to the ship extremely simple. It was so nice to have someone who speaks English pick us up in Amsterdam. This really alleviated several worries. Once on the ship, the service was impeccable. Waitstaff at breakfast, lunch and dinner were well trained, professional, and also personable. I enjoyed getting to know all the staff on the boat, including our housekeeper and captain. All the excursions were well planned and allowed us to meet some locals who spoke to us about their town and country. I feel like many of these were once in a lifetime experiences. I mean, how often do you get to bike past the Windmills in the Netherlands?!? The room on the ship was also spacious for a cruise. I stayed in a french balcony suit. My mom and I never felt claustrophobic, and had plenty of room to relax in the evenings.
I will say that Viking caters more towards older people, which I knew going in. My mom is in her 50's and she said that she felt too young to be on there. However, the service and experience made up for the lack of 20-year-olds on the boat. I still had a wonderful experience with my mom that we will still be telling stories about in years to come.