I love the Barcelo too. We stayed at the Beach in November and I'm glad we did not pay extra to stay in the "newer side" You can use any of the pools, bars,and beachside resturants no matter where you stay. We stayed for a week and had two ala-carte dinners and with a couple of long pool bar days and a couple of trips into Playa that was plenty for us.
The real decision for you may be if you will need airconditioning in the Buffets in June. If so you will want to book at either the Colonial or the Tropical.
By the way, we were also at the Iberostar Del Mar this year and I would go back to the Barcelo in a heartbeat.
Be sure to have lunch at the little place by the pier, great burgers and a nice place to play cards, have a cervesa, etc...