The impressive early sales of the unit did have us wondering, though: What exactly sparked the demand? The crisp 4.3-inch display? The unique WiMAX capability? The fact that it runs on an Android OS 2.1? Or was it the catchy pro-EVO/anti-iPhone 4 hip-hop track? (Video after the jump.)

[kml_flashembed movie="http://www.youtube.com/v/ZEBuTrSqM10" width="425" height="350" wmode="transparent" /]

What you’re watching is vlogger Tahir Jahi, “the mobile MC,” rhyming on what he says he believes to be “the first commercial rap video [made] using the HTC EVO.” Pretty slick, huh? Provided he’s telling the truth, the video and sound quality seem to come off darn well for a handset. And bonus points for keeping the song’s running time to about a minute — if he’d tried to tack on additional verses and shoehorn in a rhyme about a 1GHz Snapdragon processor or something, this would’ve felt like a bit much. (Let’s be honest: Most of the three-minute explanation/promotion/comedy bit could’ve been left on the cutting room floor, too.)

But he’s not just on-screen promoting his phone of choice; he’s also throwing shots at the EVO’s competitors, telling listeners to “lay that BlackBerry down” and calling out Apple’s iPhone 4. Check out the hook, circa the one-minute mark: “Breathe on ‘em and leave they minds blown / the EVO drops jaws like calls on iPhones.” Woof. Them’s fighting words where I come from.

Folks, if you’re anything like me, I’m sure you’re waiting with bated breath for some random Apple user to respond, because there’s nothing — and I mean nothing — more spellbinding than smartphone-centric hip-hop battles.