We took our first Grand Circle river cruise this spring (2013), on the M/S River Rhapsody, and I want to voice a few cautionary notes, to help people decide whether this cruise is for them. But first the strong positives. (1) The staff are uniformly competent and helpful. As just one example: my wife and I were each sick for a couple days. During those periods every employee seemed to know of the problems, and asked if there was anything they could do to help. The head of the dining room had special (very mild) meals prepared for my wife. (It was almost with reluctance I left the room on these occasions--I had to repeatedly decline offers of assistance.) Not once did we encounter any attitude other than an earnest desire to help. (2) This attitude extends to excursions off the ship. The Program Directors (PDs) led people onto the trams (streetcars), led them off, and continually operated on the assumption the passengers were inexperienced and needed assistance. It was a very safe and protective environment. (3) The accommodations were comfortable and the food was excellent. (A trifle ornate for my taste, but, if my worst problem is five-course dinners, life is pretty good!)
However, here are some factors you may find worth considering.
1. There is a lack of "diversity". For example; our last land tour was with Trafalgar and we enjoyed the company of passengers from New Zealand, Australia, Singapore, Canada and England. The passengers on this GC cruise are all from the US. (A fellow passenger who travels with a friend from Canada said she had to forward Grand Circle information to the friend--Grand Circle would not even mail literature outside the US.) The result is (in my opinion) a far less diverse or cosmopolitan social setting. During one meal, for example, the conversation focused on the difference in winter weather between west Texas and east Texas. [Also, do not expect meals as in a restaurant. There are no tables for two--when you eat you socialize.]
2. This tour was advertised as featuring "walking over uneven surfaces" and people were warned the PDs could modify participation or even send travelers home if individual limitations impacted the group's experience. Yet our group (which was comparable to others--35-45 people with one PD) were mostly in their 70s or 80s, with several people in their 90s. Some people used canes; one a walker, others were very hunched over. (My wife and I are in our early 60s; our choice was to offer to help the stragglers or ignore their struggles.) I trust you can envision the speed with which this large group moved, and the time spent catching up, resting, etc.
3. Perhaps our expectation of experiencing the culture of the areas we traveled was unrealistic, because--since all tours were with our group and all meals were provided--we only ate and socialized with our other passengers. Basically, we found ourselves in a cocoon of US people protectively following the PD's flag to see and be described the sights.
4. The tour literature indicated we would have internet service, although it might not always work when we were cruising. This is an optimistic exaggeration. Even when there was a connection (at some of the stops, and occasionally when traveling) I found it only accessible late at night or when other passengers were on a tour or at a meal. (Apparently having many people trying to access it during "free time" overloads the system. Someone also lamented that many people now had "smart phones" that automatically accessed any available network for various "apps"--weather, news, etc. And forget Skype or any program that requires a faster connection.) I happened to need access at least every couple days; my repeated requests for advice on how to obtain that access finally led to the crew advising me to walk into town and find a McDonalds. (Apparently all McDonalds in Europe now have free wi-fi.) Do not plan on having regular internet access.
5. Room idiosyncrasies. Our lamp lights were 8 watt fluorescent and the ceiling light had three 40 watt bulbs; not quite bright enough for me to read by, unless it was sunny. There is a reading light inside the pull-down beds, but, if you are unwilling to limit yourself to reading only while opening up the bed and lying down, bring or buy more powerful bulbs (240v, standard screw-in sockets). Also, we booked a cabin with a balcony. Turns out those are on deck 4 (Serenade deck), which is the corridor between the dining room and lounge. If regular traffic and loud conversation outside your door (especially when people line up for the dining room to open) bothers you, don't select this deck. Also, one has to go to the lounge or Sun deck to hear the intercom with a PD's description of the sights we're cruising by, so we didn't use our balcony much. [Note if anyone from GC reads this: it would also be nice if there was music available in the cabins--we didn't really care about European sports or showing one movie over and over.]
This tour had mostly repeat customers of GC, indicative that many people enjoy this level of attention, and the cloistered environment and slow pace. If you are in this category, I highly recommend this tour. However, as I'm sure GC will agree, this tour is not for everyone, and there are other reputable companies out there. I encourage you to compare.