I am very seriously considering switching my business from PC to Mac and I am in the research phase. One of the things I hear is that OS X is more stable than XP. My biggest complaint about an XP PC is that over time the performance degrades so much. My 3 year old PC needed to be formatted & XP reinstalled just so it would perform the way it did when new. Why is OS X more stable? Will I see a performance degradation in 2-3 years like my PC? Does OS X have a "registry" like XP?