I believe the memory usage has been adressed lately (either last release, or shortly after). There was an article about it on HN, which i can't find atm. Do you mean some specific use cases?
If you search for my username in that thread I asked for someone to run the code from the story on a similar dataset with PyPy. Twice as fast but x10 memory usage. But as I said elsewhere a bit of searching suggests it won't be a showstopper.
Be careful extrapolating from such small examples, where the memory usage is dominated by fixed overhead. Running Django or something similar is more likely to give a real world result, and even then, a bunch of tests is far better.
3mb vs 30mb might be par for the course for smaller programs, but either is negligible.
If you search for my username in that thread I asked for someone to run the code from the story on a similar dataset with PyPy. Twice as fast but x10 memory usage. But as I said elsewhere a bit of searching suggests it won't be a showstopper.