My wife & I just sailed the 4-day cruise to Key West & Cozumel (plus a day at sea) & had a great time.
Embarkation was a pleasant breeze: we qualified for VIP status (more than 10 cruises) & the VIP waiting lounge was well appointed & spacious. Our check-in agent took our information, told us to sit down & then personally brought us our cruise cards. We boarded promptly at 11:30 & the Lido buffet was ready. Being a Ft. Lauderdale native I'm partial to Port Everglades but I must say this Miami terminal was nicer than any here (haven't seen the RCL Oasis terminal yet, though).
Our kids stayed home, but being the summer we weren't lonely for youngsters, many of whom became unruly as the cruise went on (loud screaming & running in the halls at late hours, a 2 a.m. prank phone call - haha real funny man), but kids will be kids.