I'll try and keep this short and to-the-point. Our cruise aboard the Jade was quite enjoyable, considering our intent, which was to treat the ship as a floating Hyatt or Hilton, that just happened to dock at interesting places. The Freestyle concept works well in this instance, as does the general casual nature of the cruise line itself. If you're looking for a luxury cruise, Jade isn't for you, i'd suspect, although perhaps the suite experience changes the dynamic (which begs the question, why go to Europe in the first place if your entire time is spent in the cabin?)
We booked an inside cabin, which was quite large at around 150 square feet. We never felt cramped, and never had a moment wishing for a window. The space is remarkably well organized, and the bathroom is flat-out cavernous for a cruise ship. Considering how close you are to decks that overlook the sea, it's foolish to spend on a balcony, especially if the purpose of the cruise is not "rest and relaxation" but "discovery and exploration."
We bought their $50 soda program. I highly advise on doing so, in that you'll easily drink its worth in 3 days.
We ate at both main dining rooms, the buffet, the poolside BBQs (when held,) and at the three Asian pay restaurants. The food was great at all of them, with a notable exception being the breakfast buffet's eggs (truly gross.) Teppanyaki was awesome. I highly recommend a visit.
We didn't really enjoy the entertainment revues on the ship, however. As expected, none of these kids are going to Broadway anytime soon. What WAS unusual involved a meager interaction from the singers and dancers with the rest of the boat. We might be more invested in the shows if you put in a little effort to be more invested in us (like the rest of the staff was, or pretended to be.) It was really remarkable: they gave, at most, 15 minutes to a dance party or karaoke event and then split. As a former performer myself, that's bonkers. They have the easiest jobs on board, by far, and their interaction is the difference between a good vacation or a great one for many. If just one of them went into the crowd and invited a wallflower to dance...that more drinks sold and more ROI, no?
The rest of the crew was fantastic, however.
All in all, highly recommended.