I am a big fan of good soft tissue work. I've had ART and Graston and am a fan of both. I am also a Graston practitioner and know of several ART techniques though I am not certified in it. I think there are specific situations were ART will be more beneficial and others were Graston is more beneficial and in MOST situations a combination of both will be best.
Make sure you find a good quality practitioner though. A shitty practitioner will produce shitty results regardless of what technique they are performing.