Anybody know anything about picking good laptop batteries?

The only guaranteed good battery comes from the computer manufacturer, which is also why they cost so much. Every other battery is very hit or miss - could be OK, could be crap. Some people have really good luck with 3rd party batteries, some not so much. I'd say if you go with a 3rd party, pick one that offers a 1 yr replacement guarantee - that's the same that the original manufacturer typically offers.

Except Jeffbx mentioned, I think you can check with the seller how long the battery can last when playing DVD movie, the longer the better .

What's your budget?

Its worth it to spend the extra money for a genuine laptop battery pack and learn the proper way to extend the life of batteries depending the chipset in the battery. For OEM and non-OEM, its too much of the roll of the dice since it might be time consuming to get the replacement.

Thank you everyone for the replies and input based on what you said, I spoke to Max Capacity and what they said sounded very good based on your input and other stuff they told me about their batteries.

- Their goal is to produce a better than OEM quality batteries for people who want very high quality long lasting cells. They only use one type of very high quality cell in all their packs so all consumers experience excellent performance.

-All their laptop batteries have a 16 month full replacement warranty which turns out to be better than Dells 1 Year - sounded good based on jeffbx's comments...

-They use some type of new more expensive cell made by Panasonic called Type NNP - NCR18650 - 2900 mAh per cell.More about this later. Apparently these cells provide the best balance between long life and high capacity. Panasonic rates them to still retain %70 of capacity after 500 empty to full charges. Given that most users don't perform a full charge every day, they said that this battery will last about 3 year for an average user.

- Run time - my original Dell battery was rated at 4400 mah and 48 Wh it powered my laptop for about 1h 45min with light work. The Max Capacity battery pack is rated at 5800 mAh and 64Wh about %40 more power.

So I bought one about 2 weeks ago and my Studio now runs about 3hrs doing normal work and about 2 hrs when I watched a DVD movie on a flight to FL. Much better than the 1h 45 I got from the dell battery when it was new.

I would recomened this laptop battery [safebatteries.com] , I paid $75 for it / dell wanted 155 for theirs so the value is their!

Thanks everyone for your help and I will follow up here if something changes with the battery.
-Bart