Third Party Battery (L502x)

Hi there, i'm really sorry if anything like this has been posted before, although I couldn't find anything.

I have a Dell XPS L502X. It's 6 Cell battery which came on purchase has worn horribly, to the stage where Windows cannot even give me a correct reading for how long is left, and it just ends off turning off (without hibernation or anything) after about 15 minutes.

I'll be starting university in only a few weeks now, and I feel that my laptop is likely to require a battery - i've had a look at my options; I can pick up either a 6 or 9 cell battery, which can be either official or unofficial.

Now if I buy a new, official replacement, and it goes the way of the battery I have been using since I got my PC - I would be very disappointed.
I can buy around 3 unofficial batteries for the price of an official one, especially if it's 9 Cell i'm looking at.

Has anybody used a third party battery for their Dell XPS, if you have, how was your experience? How long have you had it, and what's it's wear level like? Also, where did you buy it from?

Alternatively could anyone suggest the reasons behind the premature failure of my current battery to prevent it happening again (assuming this was my fault) and then I could perhaps invest in a more expensive battery and hope it lasts.



Note: I'm after a 9 cell ideally, if it helps. The L502x drains a fair bit of power (understandably) and I think i'll need the extra time.


Thanks for reading my post, if you want to know anything else at all.. please ask. I'm basically just asking for a cluster of information on third party vs official batteries if anyone if confused.