[sharednothing]

Not sure why you are getting down-voted. I have 2 MBPs. One is s ~3 year old running 10.5 and his baby sister running 10.6.

This is entirely subjective per my experience:

- the 10.5 'feels' more responsive.

- the beachball is a very frequent event in the 10.6, specially Safari, sometimes even when switching tabs which is quite annoying.

- I haven't rebooted the old MBP in months. Sitting pretty on my desk. The new one has frozen few times and occasionally I feel the need to put it out of its misery myself.