A 70-300 mm f/4-5.6 telephoto lens. Sigma or Tamron?

I'm thinking about buying my first dslr (a Nikon d5100) and I'm getting the package that comes with the standard 18-55mm zoom lens.
I want to also purchase a second lens, and I find the telephoto lens to be best for everyday things. I've looked at the Nikon, Tamron, and Sigma, but because the Sigma and Tamron are much cheaper, so I'm thinking of purchasing one of those.
Which lens is best including all factors (quality, stability, etc.)? Or are they both not that great, and should I just go with the pricey Nikon?

P.S. I've also looked at the 70-200mm range zoom. If this range is better, I would't mind buying that.

I'm "jaded" towards OEM lenses.

There's only a couple of Sigma lenses I would buy and the price reflects the quality of those particular lenses ($15, 000 to $26, 000).

When it comes to "Tammy" (Tamron) lenses, years ago I bought two of them due to a tight budget. They both developed issues. They were sent to Tamron for warranty repair, only to be told they were gray market/import lenses and would NOT be repaired by them and I would need to send them back to where I bought them. I sent them back to the place where purchased (along with the receipt), and was told "The receipt doesn't show the serial numbers. You can't prove those are the lenses you bought here".In other words I was SOL on fairly new lenses.

After that, I only buy Canon glass for my cameras.

I've never owned aftermarket lenses, but seen many people who do complain about them.

I've got the Nikkor 70-300mm VR for my D5000 and I'm 100% satisfied with it.