I’ve been with the new “cat” (Snow Leopard) for 48 hours now (got it a day before). Here’s a quick review (can’t be really called a review):

It was the single most painless upgrade i’ve ever been though.

Most of the applications worked.

Microsoft Messenger for Mac did not work, but it’s a piece of **** anyways (Adium rocks!).

Quicktime X is fast and looks absolutely brilliant. It also works brilliantly well, compared to older quicktime versions.

Everything is smooth, sexy. Not much different in the GUI department to Leopard, but so much faster and smoother.

Multi-tasks brilliantly for a 10.X (and not 10.x.x) version. Stable as well.

Runs fine on minimum requirements, unlike the most recent version of Windows (i’m talking about Vista, not about 7 which isn’t out yet).

Installed in about 35 minutes from a USB DVD drive (my Mac Mini’s internal superdrive occasionally has problems, so I went with the safer path).

Adobe Air apps work fine, without any problems whatsoever.