USPSA equipment survey for guns used had the following percentages:
2019
Brand prevalence: SIG 35%, CZ 22%, Glock 18%
Model prevalence: 320X5 21%, Shadow 2 15%, G34 14%.
Optic prevalence: DPP 33%, Romeo 1 24%, SRO 15%.
2018
Brand prevalence: SIG 30%, CZ 28%, Glock 16%.
Model prevalence: 320X5 16%, Shadow 2 12%, G34 9%.
Optic prevalence: DPP 33%, Romeo 1 28%, Venom 10%.
CZ is ahead of Glock but Sig is way ahead of both.