Took cruise sincere a friend on the China tour / cruise told us how well the chef on that tour accomodated people with special diets. We contacted the Viking agent, discussed our problem in detail with her and sent her a copy of the dietary restrictions. We were told they wouldn't be a problem and that Viking was known for their ability to customize experiences for their passengers. Long story short, the chef refused to accomodate the diet (like how hard is it to make a plain piece of chicken?) and towards the end of the cruise, he wouldn't even make a steak without butter for another passenger who was lactose intolerant. It's hard to explain to other "guests" why you aren't eating the main dishes. It's also hard to tour if you aren't getting enough protein. Thank goodness we brought peanut butter along with us. My wife wrote Viking and we did get a call from a representative who didn't offer any credits or consideration.
Other than that ruining the trip, the sights were great, the rooms were adequate and the tour guides were very good.
Cabin was small but efficient and the cabin staff were excellent.