After I originally emerged amarok I noticed that I had the option to switching my database engine from sqlite to mysql. I went ahead and picked MySQL since it was already running on my system. So now I am wondering if I use sqlite if it will run faster... which is a better performer for amarok? Speed, memory whatever?

MySQL is often faster, especially with huge Collections.

And if you already have MySQL running, it probably means less memory usage. If you run MySQL just for amaroK, there probably a net gain in memory usage.

But yea, MySQL is pretty much always faster.