Is a 2-ton Floor Jack sufficient?

[zmanH2]

I have a 2-ton floor jack similar to this one:
http://www.autobarn.net/mvpf-365.html

Now I know that the H2 weighs approximately 3 tons but since you are only lifting a portion of the vehicle when you use a jack, will the above be sufficient? (e.g. flat tire repairs / tire rotations / brake repairs)

[CslRkH2]

I have a 3 ton jack and it seems to be on the light side. It could be the model I have, but just tonight it was struggling. Make sure it has a good lift, it takes quite a bit to get the front wheels off the ground even with stock suspension