IME there not worth the time & money , they do clean the gun of grease & oils and light fouling and requires some periodic brushing but dosent clean the carbon build up on cylinders ect.
You can get better results with carb or brake cleaner (not for use with polymer parts) if you have compressed air its even better for a deep clean or flitz metal polish cleans up the externals parts pretty good . they do make a cleaner thats safe with polymer parts

I bought a $200.00+ ultrasonic cleaner with 2 transducers and a heater and brand name specfic gun cleaner concentrate mixed with distlled water. and was very disapointed after you clean them you have to rinse with water, dry compleatly and deal with water entrapment in those lil nooks & cranies. both systems will require all surfaces to be protected with oil.