Lurking Around

I borrowed Matze's new 70-300 f4.5-5.6 VR lens and went out for some test shots. This was one of them. A man lurking around an old kitchen.

I am thinking to change his lens against my Sigma APO D f2.8 70-210mm lens, which is a very good lens as well. I'm not quite sure.

I'm not really using the Sigma anymore, but also have the 18-200 VR lens.

So I would just get 100mm more ( I also have another 300mm f4 APO lens).
The good thing about Matze's lens is that it is relatively lightweight. I don't want to carry around too much more stuff (my camera bag has around 8 kg when it is fully loaded - then I don't want to carry around these heavy lenses).

So the deal for me would be:
Change a lens that I am not using against a lens that I would perhaps use a bit more.
Not quite elating I guess.

Do you have any suggestions?