Can anybody who's used 3rd-party external batteries with a portable DVD player share their experiences? They have one from Energizer at Best Buy priced at $100. There is also a Memorex one at Circuit City for $80. Walmart has one from Initial for $55, but they're out of stock.

Is there any difference in functionality between any of these? Any options I've missed?

I have the bigger of the two for the initial that I got in Hong Kong. Its good for about 3+ hours. I think the Energizer is good for about twice this but it is bigger in size. Dont know about the memorex.

get the Energizer er-dvd. I was going on 6 hours with the battery til the flight landed.