I have found GeoVerify to be accurate most of the time, but not always. I have shopped a technology store twice at the same location. The first time, GeoVerify gave my location as about 4 miles away from where I was, even though I was right outside the mall where the store is located. The second time, the same thing happened. I notified the scheduler, who replied saying that the location entry for that store in their database was incorrect. Once they corrected their records, my GeoVerify code put me right where I had taken the reading.
Be aware that some MSCs do not use the GeoVerify code, even though their questionnaire asks for it. I routinely GeoVerify my location when I shop a different technology store, and it is always accurate. However, that particular MSC does not use GeoVerify, so in my shop log for them, I have zero confirmed GeoVerify codes.