|I prefer hardware arrays in almost all uses.|
My opinion is that the hard drive is the slowest part of the system. Normally raid arrays offer some level of drive accessl improvement. As to how much is depending on your system and use.
Why would you think a raid 5 is slower? It is faster in all ways that I know of.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10