OK, so my traveling group had the luxury of experiencing concierge on the Wonder last year. We booked the 2BR (4 adults & we had a 25% coupon from a previous sailing on the Fantasy). It was a 5 night cruise and the price was just a bit more than booking 2 Cat 5 rooms. We enjoyed concierge. We enjoyed the "free" water and drinks. It was nice being in a larger living space. It was nice not having to arrange any of the tastings/tickets on our own. Of course, this is very little work anyhow, so there was just a bit of value to that. It was nice being told what we were doing each day with a personalized itinerary. Was it worth the few hundred extra we each paid, you betcha. Is it worth thousands of extra for us. Nope. But that is an individual/family decision. Concierge rooms make sense for some families, they enjoy being able to order from the menus and having it delivered, the convenience of having a host, for those on the Dream, Fantasy, and now Magic, the lounge access. Or, for some that just want to be able to say they are in concierge. Or, if you have a larger family and would be purchasing multiple rooms anyhow, sometimes I think there is great value in it.
DM and I did the EBPC sailing this past October and the concierge level was 2x as much as our Cat 5. Neither of us felt that was worth it. But that is us. So no, we did not miss it. We missed not seeing our host, whom we loved, more than we missed being in Concierge. In fact, we barely even thought about it once on the ship! I think we did miss the bathroom, there was that. I think there are some CM's who suck up to you more when you are in concierge, because it is noted. Of course, we had such a fabulous group on the cruise, that nothing could have brought us down!