I don't remember ever giving Radio Shack my personal email address, but when an email from them appeared in my inbox with "Experience 3G/4G with the new HTC EVO 4G" in the subject line, I just had to open it. The "learn more" button leads to the retailer's EVO promo page, while the "experience now" button takes you to an interactive demo.
If I didn't know about the EVO before this email, I'd immediately be very interested. Who wouldn't want "dazzling multimedia performance" and "lightning-fast 3G/4G service [that] offers unprecedented speed with plenty to share on up to 8 WiFi-enabled devices"? That's so much more compelling and eye-catching to the mainstream consumer than the EVO poster Sprint has in its window.
If you don't know what 4G is (and most people walking past a Sprint store have never heard of it), "First to 4G" is meaningless, especially in areas without 4G coverage. The poster fits in with the whole "firsts" commercial, I know, but I still don't think it's very good.