@Wicked Deeds - Paul, Interesting, that LA2A deal is fantastic, I went for it too. it is the best L2A2 emultation out there, and there some very good ones, a good purchase indeed.
I understand about not sharing...
That's exactly what you should be getting, clarity, as it's not picking anything from behind the mic, it's capturing eveything that you want it to capture, the Rode NT1000 is a good mic, so you should notice the difference in the 2 setups.
I generally do a controlled environment comparison, leave everything the same, position, levels, distance from mic, vocal delivery etc. and do it with and without, and do a honest un-biased assessment, being prepared to admit that without
could be better.
Don't get too close as you'll start emphasising the bass frquencies from what's known as the Proximity Effect, mind you there are ways to minmise this if you really want a close mic'd track.
btw I did a rather long comparison of different mic configurations for mic'ing an acoustic guitar, I wanted to squeeze out the very best sound out of that box of wood on my lap, I tried mono, stereo (in a few widths and distances form the guitar) various wierd ones, the best was a tie, between a Stereo pair and a vertical MidSide, the mid side resuces slightly the risk of phasing issues, that stereo mic'ing may encounter. (Phasing is just when one mic is picking up the signal from the source a bit later/earlier than the other, which is only what a phase shifter does on purpose), there are a couple of good fixes for this one by SSL...it just shifts one signla and brings it in alignment with the other.
Hope this helps
Rich