Hi Pat, I haven't been to either resort as yet, we're going to Excellence Riviera Cancun in May.
A year ago, we stayed at Dreams Punta Cana and thought this was an amazing hotel with many restaurants, entertainments and facilities. Dreams are part of the Excellence group, the former being family orientated and the latter adults only.
From our experience at Dreams, I would have no hesitation in holidaying at either hotel, it all depends on which country you prefer to visit. Hopefully, I'll be able to review the ERC on our return.

Hi,

Many thanks for your reply.

Have decided on Mexico, but have booked the El Dorado Seaside Suites for the end of August.

Regards,
Pat