Exceptional

Liked: If you're planning to stay in the center of this little gem of a city, look no further. I can't imagine a better location. The pedestrian zone starts literally around the corner, and in the opposite direction, the castle and the cathedral are a block away, and a few minutes on you'll be in their lovely botanical garden. We drove in - a straight shot coming from the north, no turns, right to the hotel's doorstep. They have their own underground parking (for a few cars, so book early), but then you can forget about the car. The room is modern with a genius design that optimizes space and light. There is a lounge area where you can get complimentary coffee and hang out, if you want. A novel concept for hotels, and one I probably would be using during a multi-day stay. Thumbs up, Okko Hotels!
Disliked: I know, nothing is perfect, but this stay came so close that I can't think of a nit to pick...

We were warmly greeted and...

Liked: Well designed room, very comfortable. Access to lounge with drinks and snacks provides excellent value for money.
Disliked: Nothing

Very good

Liked: Its location is very convenient for a visit to Nantes.

Excellent service, location and cleanliness

Liked: Location, parking available, breakfast

Perfect location between the chateau...

Liked: Free lounge area well equipped. Free coffee and snacks
Disliked: I like everything

Very good

Great place to stay in...

Exceptional

Comfortable, clean, excellent location.

Liked: We only stayed one night but found the hotel to be clean, comfortable, and very conveniently located. Staff were helpful and always available. We didn't try the breakfast so cannot comment about that. There are many coffee shops and bakeries nearby so we didn't feel the need to take the breakfast at the hotel. We parked in the garage nearby -- beware that the spaces are very small in the garage and will be a tight fit for even a medium sized car. I am not sure if the parking offered by the hotel is better.
Disliked: It's not a big issue but I did find the design of the bathroom to be a bit strange. It has glass walls that are covered by blinds that are only partially closed. So from a certain angle you can see directly into the bathroom from the rest of the room. I find it to be an odd design choice but maybe that is the design trend these days.