I used Oracle 9i before. How Does Oracle 10g feel?

A few days ago, my machine was installed with Oracle 10 Gb again. Ah, since it was the first two years, it was very slow to start. It was finally started in about 8 to 10 minutes, after using EM, I thought it was not very good. I installed the client and went back to the Enterprise Manager to handle it. Later I changed the machine name and IP address, then, I changed a lot of configuration files under my machine and set up a new listener. Ah, I saw that my machine was slow again. I thought oralce was running. It was really good to open it, now I have changed the password of the sysman user on the machine. It is depressing. When em is started, an error is reported. I opened the Enterprise Manager and the user was locked, later, I entered the name in SQL/plus and finally got it done.