reliable private transfers IBK Servicios http://www.rdshuttle.com/en/contact_us.html
Dreams has GriGri divers onsite, Iberostar has Dressel Divers onsite. Both are great dive companies but if you are after a more personal experience I recommend using DivingDominicanRepublic http://divingdominicanrepublic.com/ they cater to smaller groups so can tailor the dive to your personal needs plus you won’t have to share the dive with 20 others
Beach wise, Dreams has great snorkeling right off the beach and you can walk into the fishing village of Bayahibe from there (5 minutes walk along the beach). Lot’s of nice little bars and restaurants around the 2 picturesque bays. Perfectly safe just keep your street smarts about you.
Iberostar is a 5 minute/US$10 cab ride from Bayahibe, in Dominicus - a small resort town, shops, banks, a few restaurants but with nothing on the beach. The beach is longer at Dominicus but the water can be a little wavey (it’s flat calm at Dreams 95% of the year). Iberostar does have a nice beach bar right on the beach around a faux lighthouse.
I like the fact that you don’t have to reserve the a la cartes at Dreams and you don’t have to wear a plastic bracelet either. Plus there are things to do and see off resort at Dreams so you don’t feel trapped.
Have fun where ever you end up!