I got my copy Friday and installed it that evening. Took about 45 min, which I don't know if that is faster than Leopard was or not. Apple claims it installs faster, but it was Oct. '07 when I installed that and I don't remember. Installation went off without a hitch. I did do a full, bootable clone on an external of my old configuration before the upgrade just in case though.

My initial impressions is that it is much, MUCH quicker booting up and shutting down. Initial boot is the same - you get the chime, grey screen, Apple logo, etc. Once you type your password and hit enter in the log-in screen, it is literally about 3 seconds and you are ready to work. Dang near leaves skid marks on my desk. Shut down is the same. I tried a shutdown with Mail, iCal, iChat, and Safari all still running. Once you give it the "ok" to shut down, it was boom, boom, boom, apps quitting, and then black screen. Couldn't have been 5 seconds total. Almost quick enough to make you think the shutdown process went awry and it crashed to a stop rather than a controlled shutdown.

All of the standard issue Mac apps open quicker too. I have iCal populated with several calendars and it used to take about 15-20 seconds to fully open and be ready to use - dock icon bouncing the whole time. Now - one bounce and you are in business. In fact, I haven't seen more than one bounce on any of the Mac OS X apps yet - they are all 64 bit now. Other apps run about the same speed as before - but they are all 32 bit yet. Look forward to updates on those to 64 bit.

I really like the new stacks grids. New color scheme that seems easier to look at and now have scroll bars if all the icons don't fit the grid. Major improvement there. Also a big improvement - if you have subfolders, they now open in a new grid rather than Finder opening up.

Quicktime X - new interface, looks pretty. Videos won't start on their own without clicking play - bad. No preferences in QT to change this behavior either. There is a command that you can punch into Terminal to change it though - but I'm not changing anything this early in the game.

The only bug I've ran into so far was changing folder icons. Seems like 2 attempts are needed to get them to "take".

All the apps I have tried so far have worked (3rd party), but have not gone through all of them yet. Istat Pro menubar doesn't work. I used that to monitor temps, network usage, etc - minor loss, but I'm betting they have an update coming within a couple of weeks.

Apple is already working on 10.6.1 - developers were seeded this Fri - so we will probably see an update coming in a couple of weeks. Same thing happened with Leopard - .1 came only a few weeks after release.

One thing to keep in mind if you upgrade - your Flash revision gets backed up to a version with a security flaw. You need to re-update to get the latest version. The story from Apple is that the older version was current when the SL disks went into production. Since the new Safari is a brand new 64 bit app, the old one gets wiped and the new replaces it. The newer version of Flash gets wiped with it. Do not forget to do this!

Would I recommend? Heck yea! At only $29, you can't go wrong.