It's absolutely worth it linx. Mainly to use custom, optimised versions of the OS. The main guy who makes them, Cyanogen, is a genius. He already has a G1 ROM out that basically contains all of the Donut 1.6 update.
It is lightning fast compared to the stock ROM and has a ton of optimisations and bug fixes that even Google hasn't fixed yet.
The second great reason to root is so you can run apps2sd. Basically you create a partition on your sdcard and all your apps get stored there. Before I did this, I had about 75 apps and had major slowdown. I was always having to uninstall stuff if I wanted to check out new stuff. Now I have about 140 apps with no slowdown at all.
Third best reason is to enable overclocking. Although the G1 has a 528MHZ processor, for some bizarre reason, it only runs at about 400MHZ on the stock OS. Once you have root access you can download Open Overclocker from the market and push it up to the max - it makes a BIG difference!
There's no excuse for not rooting now, because it's piss easy with the new method. Before, it was a little bit more complex. When I rooted back in February ish, it took about an hour, including partitioning the sd for the first time. Now with the new method you can do it in 20 minutes or less, including partitioning the sd.
Here's what I would do if I were you:
1. Backup the contents of your sdcard to your computer.
Then
use this guide
to create a 500MB EXT2 or EXT3 partition on your sd card. Move your files back on to your SD once you are done.
2. Download "My Backup" from Android Market. It's a fully functioning 30 day trial. You won't need to use it to restore in all likeliness, it's just a precaution.
2. Backup your apps and data using it.
3. Download the app "Recovery Flasher" from
here and install it on your phone.
4. Run that app and backup your original recovery image.
5. Use that app to flash the Cyanogen Recovery Image.
6. Check that it has worked by turning off your phone, and turning it on whilst holding the "Home" button. If it has worked, you'll see a screen that looks like this:
7. Select the top option to reboot and get back into your OS (whch will still be the unrooted stock OS as we haven't flashed a new system image yet, only a recovery menu)
8. Download "CM Updater" from the market. This is an automated program that will download the latest CyanogenMod OS (latest stable version is 4.0.4)
9. I believe CM updater will download the file to a folder on your sdcard called "cm-updates" by default. After it has downloaded, do
not select apply now. That won't work this time, but you'll be able to do that in the future, for future Cyanogen OS updates. It won't work yet because it requires root access.
10. Use the app "Linda File Manager" to cut the update file from the cm-updates folder and paste it to the root of the sd card. Rename the file to update.zip
11. Once you have done this, turn off your phone and get back to the recovery menu by holding the Home button while you power on the phone.
12. On the recovery menu select the option "nandroid v.2.2 backup" - this creates a backup of your entire phone image, in case something goes wrong and you need to revert it back to how it was. It's wise to do a nandroid backup any time you flash a new OS.
13. After you have made a nandroid backup, on the recovery menu, select the option "apply sdcard:update.zip"
14. It will then flash the new OS. When it's done, select "reboot".
15. Your G1 may take 5-10 minutes or so to boot up now, but don't worry - that only happens once after you flash a new OS.
16. When it boots up, congrats! You now have a rooted G1, with apps2sd, running Cyanogen's super awesome modified OS.