Okay. I've been running Tiger now for about 24 hours. Rather than work on my CS184 final project, I'll tell you a little about my experiences. This isn't terribly well organized, but I want to write things down before I forget them.
In a nutshell: there were some frightening hiccups along the way, and some bizarre behavior by the Spotlight indexer, but it all seems to be working fairly well now.
Specifics
First off, I'd like to express my displeasure that while Apple has labored to create wonderful new features and eye candy, they still have not fixed small nagging bugs. For example, auto-scroll in list view in the Finder (and other apps) still does not work. There are also things that Apple refuses to fix, claiming they are by design: you still cannot let go of a scroll bar, and single-line edit fields have a broken selection model (someday I'll post a detailed analysis of why it's broken, and why the Mac OS 9 model is superior).
Before I complain too much, I'd like to point out that Spotlight is a pretty nice feature.
Installation
First hiccup: when I was updating my system (I chose to update, rather than "archive and install" or "clean install"), I was unable to deselect any of the additional languages. My very smart friend at Apple suggested that was because I was doing an update, and perhaps the existing system already had those languages installed. While that may be, an app should not provide me with an enabled checkbox and then not let me check it, and it should provide explanations.
I had PGP 8.0.10 installed, and the Mail plugin is horribly incompatible. This is not the first time PGP broke Mail, but it took my very smart friend to suggest it. After laboring to find the plugin, I removed it, and Mail worked again. Mail is much faster at some things, like deleting a bunch of messages. They also added the option to bold a message line if it was unread. But there are still many annoying quirks to Mail: it still breaks long URIs (I've heard the team is very sorry, that this fix just didn't make it, but is scheduled for an upcoming update; nevertheless, it's a pretty big bug, as it affects everyone who receives long URIs sent from Mail and who does not use Mail). Mail has other problems, too. In general, though, it seems to be faster. Note that Mail now stores each message as a separate file, so that Spotlight can index it well. Hopefully this won't overburden the file system. If it doesn't, then this will bring many improvements, not the least of which are improved robustness and more efficient backup (you don't have to back up your whole email store just because one new message arrived).
There's a PGP update coming someday.
Spotlight
This is the only feature, so far, that really pleases me. It has a robust, C-like query language, and seems reasonably fast. On my 60+ GB of data, the indices take up less than 1 GB.
When you first install, Spotlight must index your drive. After that, the file system updates the index every time a file is written. My very smart friend assures me that this is fast, and doesn't impact performance.
At first, Spotlight estimated 35 hours to index my drive. After a while, that went down to a couple of hours. Then, suddenly, it was done. I was able to search for a few things. Then, it was back to indexing. Then it was done. Then it indexed some more. All very bizarre, but in the end, it seems to have my disk indexed.
I've already created a smart folder that searches the Mac OS X 10.4 SDK (another good new addition: separate SDKs for separate OS versions) to find stuff in header files (suggested by my very smart friend).
CodeWarrior 9.0
That CS184 final project I'm avoiding? At first it wouldn't build after I installed Tiger. So I created a new project from stationery, and removed an #include <unistd.h>. Some experts on a list suggested that I didn't have the latest CW update installed, and they may be right. But that same list also had some traffic recently about the update breaking other headers in Tiger, so I'm reluctant to install it. At least I got my project compiling, and I don't really need getopt().
Since Apple keeps usurping command-key equivalents, I've moved my "find header file" key to be Command-Option-`. For some reason that no longer works, but I can't figure out who owns it.
Adium X
I use Adium X for chat, so I won't get to enjoy the new iChat very much. The only problem I've experienced so far with Adium X is that my iChat sound set broke. This is because it used Aliases to refer to the original iChat sounds, so I had to do some manual fixing to get it to work. It's almost where it was, but the new iChat seems to be missing the "1st IM" sound it used to have.
Finder
Autoscroll in list view still broken, but FS notifications are finally hooked up, so files should update instantly (rather than you having to deactivate and reactive the window).