I got the iPod from a friend who was having reliability problems with his iPod Video. I mentioned trying the iFixit battery replacement, but he wasn't game, so he bought an iPod Touch and sent me the old iPod. It had a cracked case in front of the video area, so I got the front panel and the battery.
Pretty well, except I damaged the flexible circuit going to the Hold switch. The glue holding the original battery adhered to that circuit, too, and prying out the battery pulled up the circuit, too. I had an old, partly functioning iPod Video myself that doesn't get used anymore, so I swapped the backing metal piece that includes the flexible circuit, Hold switch, microphone plug, etc. With the swapped backing, the new front panel and new battery, the iPod went back together easily, and appears fully functional. I'll have to see how battery life is, and whether any operational quirks remain.
I see the instructions have a warning triangle near the battery removal step, but I think it might be useful to say specifically to watch that flexible circuit below the battery.