T1B

So I checked with Dell, and they want $134 I found a non dell site that has a battery they say is compatible for this system, same warranty, $70-$80.

I've never had to buy non-dell replacements, so I don't know. Do the non dell products have as good a shelf life? That's a pretty big price diff.

As far as I've read, outside manufactured batteries are a bad idea, as the quality is far less.

I have never purchased an off brand battery either but mainly because I haven't owned a personal laptop for about 5 years now (jobs always supply me with one)

3rd party batteries are a big business and they tend to be as reliable as the manufacturer one. Don't forget that Dell usually undersells machines and tries to make money on accessories and upgrades so they overprice their batteries.

I would say look at the company and see if they are fairly big but I wouldn't hesitate too much, especially if it comes with some warranty.