It's a case of story and gameplay vs adventure. Since you've played Black 2, Black 1 will feel incredibly similar to you, and even inferior in some ways. It does, however, have the best story of any Pokemon game I've ever played, including HGSS, so that's an advantage to them, as well as the combat which is much faster than HG, and yet somewhat slower than Black 2 still. On the HG side of things, I assume you haven't played it? On that assumption, it'll feel like an adventure all over again, like in any Pokemon game. I'd say HG if I were in that position, but... that's just me.