I stayed there last week. It is a long way from the city, so far that you do not get the Basel tram ticket that comes free with Basel hotels. It is at the last stop of the 14 tram, about 20 mins. from the Swiss railway station. So you have to factor in CHF11 for a travel pass for a day. I was stopped by the ticket checkers on the way from the airport. Usually this is not a problem if you are on your way to a Basel hotel, as they know you will be collecting a travel pass on arrival. So the advice to anyone using the CY Marriott Basel, is to buy a ticket before heading out there. Taxi is over CHF40 from the city.
It is a good 15 min walk from the tram stop or the local train station to the hotel.
I see no reason to stay at his property if visiting Basel. In fact, ever again for any reason.