This hotel was booked for me by a travel agent based on my need for a good price and location for business that we had at the Messe ( conference center). The location was very near the Stuttgart airport which is right next to the Messe. The Mercure has a shuttle that picks up right out front of the main terminal and was very easily located. The rooms were clean and spacious (spacious is relative to European hotel rooms, hotels in the States are generally much larger). The staff was friendly and helpful and all spoke excellent English. The hotel is NOT in the vicinity of downtown Stuttgart which harbors many of the stores, restaurants and other amenities, but the U Bahn is just out front and can get you downtown in approximately 20 minutes for a fee. It would be best to research which train pass would suit your needs before hand as the ticket kiosks located at the train stops can be a little confusing if your German is lacking.
There is a restaurant located in the hotel which was OK, but the breakfast buffet they served every morning was the best I've had in a long while.

A few tips...
If you book your trip in advance, the airport Mercure hotel is priced around 79 euro a night. Last minute bookings may cost you more than 200 euro! So book early.

You will need to schedule the shuttle from the hotel to the airport as they seem to only have 1 van and it can fill up quickly.

If you give them your email upon check in, they will give you a free wifi pass code. This is worth it, as wifi can become expensive.

The fitness center consists of a sauna and 2 stationary bikes, so if your big into fitness, don't expect much.

I would recommend this hotel under certain circumstances. They met all the essential standards you would look for in a solid hotel experience.