We've been doing adults-only AI resorts once or twice a year for the past 10-15 years or so and have been to most of the ones listed and several others. We only went to LeBlanc once because we really don't like the high-rise Cancun scene and prefer resorts in a more "natural" setting. That being said the service and food were all some of the best we have had, although the basic room at LeBlanc felt much smaller than any of the other adults-only places we've visited (more hotel and less resort-like). We don't spend much time in the room, but the single sink bathroom was tight for 2 people trying to get ready for a nice dinner at the same time. It's something small, but at this price point was annoying. I think you would have to upgrade to one of their top-level rooms to get a double-sink bathroom, but you can splurge for an anniversary
We've been to Secrets Maroma at least 5 times (I've lost track) so we obviously like it because we are beach people and not interested in sitting at the pool. The soft, wide white-sand beach is really nice and there aren't a bunch of other resorts nearby even though it's only about 30 minutes from the airport. The food and service are both good here, and I highly recommend going preferred club room because of the reserved beach section where the palapas are spaced a bit farther apart and have nicer loungers and also access to the new private beach club/restaurant that they have added. It also puts your room in buildings closer to the beach with better views. I also suggest selecting an ocean view room so you are in the top floor, especially if you are light sleepers. People dragging their furniture and clomping around in rooms above you can be noticeable in the lower floors. Sargassum can be a big issue here, more so in the summer and fall than in winter so keep that in mind. That being said, they do work hard with teams of staff out raking the beach or collecting sargassum with a tractor.
We just went to Secrets Akumal last winter and would definitely return. Very similar product to Secrets Maroma, but we found the food not quite as good but perhaps we just haven't found our dishes yet. The beach is not as wide or open as Maroma, but is really nice. The snorkeling right off the beach was a big plus seeing sea turtles, stingrays, lots of fish. Because the resort is right next to a turtle sanctuary, there are no motorized water sports and we enjoyed the quiet and not having to hear jet skis all afternoon. If I recall, they do have a sargassum barrier although it was winter when sargassum isn't usually as big of a problem so I don't know how effective it is when sargassum is peaking. I don't think preferred club is necessary here since it doesn't really get you much extra. It's farther from the airport, but really only took just over an hour to get there.
I think all Secrets products will have the nice pools with swim up bars, good food/drinks, activities and evening entertainment you are looking for. We haven't tried Moxche yet, but it looks beautiful.
As others have said, sargassum could be problematic at any of these resorts especially this time of year, but north of Cancun is supposed to be better.
