When I installed it, I decided to go for the archive and restore as opposed to the upgrade, as I thought this would give me a faster, cleaner system.
So, I started the archive and restore process, everything went fine until it tried to restore my files at the end and it came up with an error saying 'Install Failed'. So, I rebooted, and tried the upgrade after that, and that seemed to work ok, apart from the fact it created me a new user account and didn't copy any of my stuff over.
However, I needed all my files, and to be honest, couldn't be bothered customising everything again.
So, I set to work finding out what was causing the migration assistant to fail, which, by the way is the program that the Leopard installer uses to complete the archive and restore. I traced the error to a strange cache file, which appeared on disk, but didn't exist. Using rm -rf in the terminal didn't work, so, I enabled the root account, trashed the entire cache for my old user account, then ran the migration assistant again. Fortunately it worked that time. :-)
My advice, is if you are upgrading from Tiger, and wish to archive and restore, trash the Cache directory first. :-)
After a bit of mucking about moving user files about, I finally got my system the same as it was under Tiger.
User Interface, User experience, settings:
The whole user experience seems very smooth under Leopard, except for a couple of UI glitches where finder Windows open too high up and appear to go under the top menu bar, which is odd. I''m sure they will be ironed out by 10.5.1 though.
The system preferences are definitely much improved from Tiger, they have added an option to use folders other than your home folders for SMB shares, which is definitely a good thing, specially on my system, which has 4 hard drives, and 750 GB of files in various places.
Netinfo manager has gone, but the same settings are available in various different places, such as in System Preferences, and for NFS and mounts and shit like that, the settings are in Directory Utility.
Stacks are great, some have been quite critical of the grid, but I disagree, it beats having to open a Finder window.
The coverflow thing in Finder looks nice, but yet is quite pointless as far as I can see, why bother having that when you get previews for every file, and you can hit space bar to get a full preview with Quick Look. Finder, in general seems to be a lot better, the new icons are very nice too, and it will do an icon preview of most files, including avi's which it would never do before.
Spotlight seems scarily faster than Tigers spotlight, and will do much more efficient boolean searches.
Time Machine, very customisable, you can back up whatever you want, and it seems to be quite efficient. It's extremely easy to restore from a backup too. I have it backing up to my smallest hard drive, and although it has produced about 25 backups so far, it hasn't used much more space than it did with the first backup.
Spaces is a very good idea, and it appears to be a good implementation of it. I have set it up so Vmware fusion uses space 2, so it doesn't clutter up my main workspace with Windows, not that I use Windows that often, but it's nice to have for Office 2007 and msn webcam support if nothing else. It's very easy to switch between them and it multiplies the available desktop space a lot. Definitely very useful, but nothing new, because it has been in Kde for ever!
In general, user interface wise, it is much cleaner and tidier than Tiger, and it seems to be easier to get to places that you need to get to.
The UNIX backend of OS X is very much as it was, nothing much really has changed. Memory management seems to be much better however, and the whole system backend and a lot of the frontend is allegedly 64 bit now so it can address more memory on high memory systems.
The terminal app retains all of its power, you can even have tabbed terminal sessions now.
One thing you might notice, is that all your user apps now run under launchd, instead of running under windowserver like they did previously. I believe, but don't quote me on this, that this is the sandbox feature that protects your system better from malicious software.
I haven't really had a look round inside to see what unix components have been updated, but i'm assuming that many of them will have been updated components. Samba is at 2.0.25b, which is pretty recent.
Mail 3.0 does not bloody work properly with my MDaemon imap server. It will not download the headers, and basically wont do anything. :-( So for now, i've had to download Thunderbird (yuk), until Apple come up with a fix for it, which hopefully will be soon, as I have put in a detailed bug report.
Last.fm application doesnt work properly, and its shit anyway, so I downloaded iScrobbler instead.
Couple of UI glitches specially with Finder windows.
Front Row uses an excessive amount of memory, and doesnt appear to terminate itself once you exit it. Might be a candidate for being disabled if it persists in that behaviour. :-p
Anyway, thats about it for now, if theres any more, i'll either do an edit or a new post....