The md421 is probably one of the best tom mics ever produced, one of the most common drum and guitar cab mics used by major studios, and is a high quality dynamic mic with a longstanding reputation. The NT1 is a bright, cheap condensor that some people think sounds great on vocals. I've never heard of anyone using an nt1 on drums if they had a 421 handy (except maybe for the bottom of the snare) However, the 421 isn't a very popular vocal mic.They are two completely different mics with very different applications and they have almost nothing in common. I don't know why anyone would compare the two. You will eventually grow out of an NT1 and want to upgrade. You will probably never grow out of an md421. For toms, there are a million mics I'd use before I would even think about grabbing an NT1. Does that answer your question?
