Closed MRIs come in 1.5 and 3T. They are narrow but offer great resolution and less motion artifact especially with good technologists. 3T is necessary for many body imaging e ams such as multiparametric prostate MRIs to avoid using an endorectal coil.
Recently, a third option has become available called wide short bore MRI. These scanners have a shorter wider bore the patient enters. They still offer 1.5 and 3T capabilities as the narrow bore magnets and can accommodate larger patients and those with claustrophobia. Most hospitals are replacing their scanners with this newer generation. They are more expensive so many imaging centers are holding off on purchasing new equipment until their scanners are end of life.
Bottom line, the best quality scanner is closed MRI and the wide bore is more tolerable for patients.