Here is a simple chart illustrating the tuning accuracy of Evertune bridge in V25-ET guitar. Not a scientific study but simple 12 day 1 measurement per day with Peterson StroboSoft PC software.
Guitar was played daily basis and used also in band training sessions. Also some temperature changes up and down happened during the period. Chart shows that every string tuning deviation stays pretty much in the pipeline plus/minus 1 cent of the original, which is a great result.