Nice to see others that bought the 2006 modelMine has been chugging along since 2006. I can't upgrade beyond Mountain Lion according to Apple.
It's slow... and it's time for me to get a new one very shortly. Surfs the internet fine, runs Eclipse for coding fine, just noticably slower than my 2011 Mac Mini.
Right now the battery doesn't work on it (says it needs servicing) - (this is the 2nd battery I've had for it). But I've continually used and charged it for 2,000+ days now, it can be expected.