Buying a laptop battery - OEM vs. 3rd party

Looking at a replacement 9-cell battery for my Dell 1525 I've noticed that the OEM batteries that Dell sells are up to 3x more expensive than batteries sold by a 3rd party vendor. Is the Dell premium worth it? What experiences have you had buying replacement batteries?

Honestly, I have never had a problem with third party batteries where the specification matches.

However, if your laptop is still in warranty, I would only use official ones as they will probably use this as an excuse not to service the laptop.

If the laptop is out of warranty, I would personally use a third party battery.