there is still difference in the tone, and both r colors that most like, i say if you like darker shades, it is alrite. Unless of course, you are looking for both of these choices to be entirely different.
I have an '08 black City and just purchased an '07 anthra City. If you are talking about an '07, then it will be very different from black as it has blue/green tones to it. It is one of my favorite colors, too. So, I say, if it is in good condition and you love it, get it!
I'm in the minority in that I would just stick with black.
I tried out an 07 anthra City thinking that it would be a cool colour to have as an alternative to my black Bbags, but I bought without having seen the colour in real life and just didn't love it in person. I ended up always giving her a miss and reaching for my black ones instead.