Effectiveness of parallel/distributed application control based on predicates defined on application global states depends on the performance of an underlying Consistent Global State monitoring mechanism. Focusing on Strongly Consistent Global States (SCGS) usage, we introduce three measures of SCGS monitoring quality. They reflect delay, state information ageing and state inspection frequency experienced by a monitor. Using the measures, four SCGS monitoring algorithms are compared, including two novel algorithm variants. The comparison is carried out with the use of simulations. The newly introduced algorithms prove to perform much better than a standard SCGS algorithm.