I ended up updating 6 3DSes using
Plailect's Guide. If you don't screw up, the process takes about 4 hours to complete. The tedious parts are the backups, and transferring them. It's great to be able to backup all my game cards, and have them all installed on the home menu. I was able to copy all my save game files over, too!
It's a good time to mod your 3DS. I looked into this last year, but all the information was spread out, and there wasn't a9lh, yet. Now, you end up with a 3DS that can boot into CFW, and have the latest update, and also access the store!