I tested 'em all out... at least 5 popular blocking and call manager apps. Hands down Black & Whitelist took the cake because it clears the phone log after it blocks the call. You still hear a tiny "Beep" as the call is initialed and sent to voicemail and that's true for ALL the apps. Used a coupon on Handango and picked it up for $20. i,softwarelabs: A Phone Call Screener blueprint for Blackberry phone.
Google search for Handango coupons and you'll save $5 off this purchase like I did. I love it. Be warned that the menu options don't work with OS 4.5 so you have to type each phone number in manually until they update it.