I've used Google Voice, MyHumans, Nomorobo, Callblock, Truecaller, Robokiller, and plenty of others to try to control the constant spam calls I receive every day and none of the services have worked effectively.
Pepper, on the other hand, has been flawless. Not only have I not received a single spam call since setting up the service, I haven't even received a single spam voicemail. The 5-6 spam calls and 2-3 spam voicemails I used to receive every day has dropped to zero. I could not be happier about this change!
One of the best parts about Pepper is that when my contacts call me and end up leaving a voicemail, they don't have to deal with a robotic, impersonal voicemail message. Instead, Pepper allows me to record my own personal voicemail.
The only downside to Pepper is that because it is routing calls through another phone number, there's a noticeable delay between pressing the button to answer a call and the point at which both sides of the call can hear each other. I usually have to say hello 2-3 times before I am heard on the other end. However, this is a small price to pay for this brilliant service.