By waiting though you risk not being able to simply return it for another model should HTC not deliver on their promise. I would be wary. One Rep's word over the phone won't mean a thing to AT&T later if HTC doesn't deliver. What if it turns into 2-3 months or never?
Not trying to be a Donny Downer, just saying one should be wary of verbal promises when dealing with just about any product. I'd return the thing and check back in 2-3 weeks, or monitor this forum for feedback.