When you think of caller ID spoofing cards, SpoofCard is the brand name often thought of first. They're a generized trademark: the Klenex of tissues, the Q-Tip of cotton swabs, or the Band-Aid of medial bandages. With the newest features available today, they're the best choice for caller ID spoofing.
Stealth Card isn't much more than a re-branded, higher-cost version of SpoofCard. It seems the only benefit to Stealth Card is that you can choose to have recorded calls e-mailed to you.