I liked the C1000s more than I liked the NT1A.
Neither is a bad mic, and good technique and discipline are going to pay dividends.
Here's a thought, though. The C1000s takes a battery, and I needed it because I didn't have phantom power available when I started out.
I liked it on snare bottom, too. It would also work for snare top, since it can take some serious SPLs.
Rami's comments are spot on. He's a good drummer and the mics do a fair job of capturing his performances. Are there better mics for Rami? Probably, but the ones he's got aren't ruining his performances. Much still depends on skill and patience. Have both is good supply, or this will become a very expensive habit indeed.
If you already have a pair of C1000s, I wouldn't lose them for some 603s or anything. But if you're looking to buy new, I'd look for something a little more versatile.
Maybe a pair of studio projects B1s? Not SDCs, but they take SPLs and I belive have multipattern options, which will keep them in use long after you've found a replacement for the C1000s.
You're not going to hear a monumental difference until you're willing to part with a grand or so.