We stayed at the Akumal Beach Resort for my sister's wedding. We had about 40-50 people in our group, so with the bus to your group, you don't have to make all the stops at the resorts along the way. The extra stops is what adds time to the trip. Most people didn't find the trip long at all, but it definitely does take away a few hours of beach time that you could have had at a closer resort.
If you do choose to stay at the Tulum location, make sure that your guests don't go get completely drunk the last night they're at the resort. The bus ride is pretty bumpy and speaking from personal experience, isn't fun when you're hung over. We had a few very sick people on the bus on the way back. Too much fun! Longest bus ride of my life! (on the way back.)