I just purchased an AKG C3000B. Since I don't own the Rodes NT2, I can't recommend one over the other. I will say that I'm quite pleased with my purchase.
I bought
the AKG C3000B to record vocals. Prior to buying it, my main vocal mic was an AT3525, which by the way is a pretty decent mic. I wanted an upgrade from the AT3525 and the C3000B has gotten very good reviews in Electronic Musician, Recording Magazine and Home Recording recently.
I've been experimenting with the C3000B all weekend, and so far I'm very pleased with my new purchase. For vocals, it does sound better than
my AT3525--it has a fuller sound, especially in the mid-range.
Today, I decided to try recording my acoustic guitar with my new mic and was very, very impressed. It really does capture the true sound of my acoustic more accurately than the pair of AKG C1000's I have used over the past couple of years.
Anyway, I'm really pleased with my purchase. I think the C3000B has been a great addition to mic cabinet and it is a mic I will use a lot to record vocals and acoustic guitar.
Sorry I couldn't give you a comparison to
the Rode NT2 but I hope this information helps.