Using the Tiger
OK. Tiger is cool. Let's get that out of the way first.
Dashboard now makes sense once I've had time to arrange it. Press F12 and you get a variety of goodies: weather, time, calendar, dictionary and more.
Spotlight is fast on a G3/700 with 640MB of RAM. Use it--it's like Google's Gmail searching. Don't think, just search.
The new Mail.app? Still getting used to it, but the searching there is fast. I'm looking forward to smart folders and such.
Rex Hammock: back up and install the Tiger. I found out what my Backup and restore issue was--I was doing too much at once. After the first reboot, get everything set but don't run any apps, then reboot again. Restore from backup and you're done. Mail.app correctly imported junk mail settings, address book, keychain, rules, everything.
More tomorrow after I've had it for 24 hours. A solid upgrade--nothing earth-shattering--but worth my money.