In article rks, Chef
Bodini wrote:

How important is this feature in a telephoto lens? I'd like to purchase
a lens for my d200 in the 400mm or better range. It would mostly be
used for wildlife photography as I live very close to a national park
(elk, wolf, birds).

for handheld use, stabilization is highly recommended. if you are going
to use a tripod, it's less of a requirement, but it can still help even
on a tripod if it's not rock steady. you can always turn it off if it's
there, but you can't turn it on if it's not there.

Many of the OEM brands (Sigma, Tamron) offer telephoto lenses and I'm
wondering if they're even worth looking at.

it depends on the lens. some are good, some are not.