3 Night Stay Recommendation - Flying into Cancun

Flying into CUN late July. Initially planned to stay in Isla Mujeres, but debating whether it would make more sense to stay mainland due to short nature of trip.

Few questions:
1. For those familiar with making the trek to Isla, does it make sense logistically to try and spend the extra travel time for a long weekend? We get in at 11:30 AM on a Thursday and leave 5 PM on Sunday.

2. If Isla is doesn't make sense logistically, any recommendations on staying somewhere in the Cancun or Playa area? We aren't all-inclusive fans for the most part, but we'd entertain both ideas given the right price/location etc.

a. All inclusive option that is more boutique style than for the masses.

or

b. Non-inclusive option that is in a good location with nice beach and can take transportation relatively easy to get to nice restaurants. Thinking probably in a "mid-range" budget. ~$400 or less.

Thanks!