We stayed here for two nights in February. The front desk staff were very nice and very accommodating. The 24 hour Starbucks is a nice touch, as is the option to order food-we did not but seemed convenient nonetheless.
The hotel allows dogs but you are not allowed to walk your dog through the front lobby to get in and out of the hotel which is inconvenient at best. I get not allowing pets in common and dining areas, but the lobby is a bit ridiculous. They also charge a $150 non-refundable pet fee which is a lot IMO. Other hotels have charged that, but usually a Hyatt or similar upscale chains do not charge so much. Although this is not an upscale hotel.
The rooms are ok but could use am upgrade- esp the bathrooms. I think they may be in the process of renovating because the elevators were being worked on and I think they had a notice in the room that they were doing upgrades.
The location is great. I'd recommend the Hyatt Place if you're looking for a place to stay in Mystic. But if you're going to travel with a pet and willing to pay a high pet fee, the Residence Inn down the street may be a good, if not better, option.