I would highly recommend this location inside the Park MGM hotel. Keep in mind the hotel just went through a huge remodel so everything changed. Many of the old reviews are not relevant.
This location looks newly remodeled. It's huge! With lots of seating inside and outlets. They have a full Starbucks menu including lunch items, pastries, hot breakfast food, and all the Starbucks drinks. They are very busy in the morning, but in the afternoon it's a nice place to read, sit with your laptop, or take an iced tea to the pool. The customer service was friendly and the store was clean.
The only downside is prices are higher then stores not in a hotel. Oh and I wish they stayed open later.