I've done a ton of reading and want anymore input I can get on these choices for AI's:
Royal Playa Del Carmen
Iberostar Tucan
Rui Palace PDM

I'm looking for a place for our family--and that includes 3 twenty something guys.
Suggestions?

The Royal Playa del Carmen is adults only and is right in the town of Playa. It is a great resort and only a short walk from all the action of 5th Ave.

Do you think my three twenty something sons would feel out of place there?
Is it mainly couples?

We've been to the The Royal Playa del Carmen. It's a great location since it within walking distance to 5th Avenue. However, I did feel it was more for couples than singles. Though there were singles there. Of the 3 you listed I would look at the RIU's for their age range. The RIU's appear geared more for young adults and the party crowd. However, none are adult only, so there will also be families/kids.

I vote for Iberostar Tucan.

It is about a half hour walk to town or a $5 cab ride. Beach is good, lots of space within the resort.

We like the jungly atmosphere between the beach and the front lobby.

Lots of families and we saw lots of young people the last time we were there.

The Tucan is one I keep going back to.
There is a new one opening up in December called Azur Fives...it has the right sleeping arrangement for us but makes me nervous to go there a month after it's open.
I should keep looking at Tucan.

We went as a large group and one couple wanted to stay next door at the Riu. They paid more for the Riu and I think it may have had a 1/2 star higher in the ratings but they thought the grounds of the Tucan were nicer.