Ask HN: Minimizing RAM usage: Dropbear vs OpenSSH?

I've been using OpenSSH for years now, but in looking at ways to reduce memory usage (I keep hitting 256MB on a 256MB slice) on my VPS, I saw a post glorifying dropbear, as compared to openssh. He didn't find anything he didn't do normally with openssh that dropbear couldn't do, which inclines mean to use dropbear. I haven't found a complete feature list for dropbear, one that I could compare to OpenSSH's. Does anyone else have any information?

And somewhat related, does anyone have any tips on minimizing RAM, or any other resource, usage? (Disk space being another one)