Hi There All! TA Wendy here... I have booked many wedding groups at and actually stayed at both of the Excellence properties.. they are very similar in the lobby design, and amenities, and rooms are quite similar in design as well. EPM is on a beach that is protected and very small waves due to the island of Isla Mujeres sitting just off the coast.. I find it to be the more swimmable of the two. They are both about the same drive time distance from the Cancun airport, although ERC is going to be just south on the highway and a turn in, whereas with EPM you are going through towns and residential areas and it is a bit more stop and go traffic on the drive, so could potentially make it a bit longer to get there, (and not as pretty of a drive).
Both have the same great in room, full bottle alcohol set up, and both have many swim up rooms, and also terrace suites that are wonderful for Bride and Groom! Both have great selection of restaurants, and great entertainment in the evenings. My one quibble if you could even call it that is both of their wedding "Gazebos" while beautiful, have in my opinion a backwards set up.. normally bride and groom would have their backs to the ocean, guests looking out towards the beach. This is the opposite in both of their Gazebo settings.. so B&G are looking towards ocean, and guests have their backs to the beach.. still pretty garden background but I would have designed it the opposite way, and indeed I just stayed at their new resort The Finest and they HAVE turned it around on that resort.
Otherwise Excellence is a great choice no matter which of the two you select and there are actually many locations for wedding set up. If I can answer any questions for anyone, I am glad to.. for the last several years I have been one of the top booking agents in the US for all of the Excellence group, The Beloved and The Finest, and know most details about the resorts. : )
TA Wendy from Wright Travel Agency