New macro lens for my Nikon D5000?

I want to buy a new macro lens for my Nikon D5000
i'm between the Nikon 105mm 2.8 VR or the Sigma 150mm 2.8
i want to know if its true that the sigma is very slow at focusing.

i preferably want the sigma because it has 45mm extra of focal length but if its to slow i rather buy the Nikon 105mm and then buy the Raynox dcr-250 so i can get very close up to bugs ect.

I want know of personal experience if possible.

IF you have the budget and you want to go insect huntint the sigma is very interesting, tamron also makes a long macro lens. Do remember that a d5000 needsa motorised lens to autofocus. PErsonally I find AF in macro rather useless

I would recommend you Nikon 105mm f/2.8G ED-IF AF-S VR Micro-Nikkor Lens
If you want a portrait lens or a macro lens then this is one of the two best rated 105mm macro lenses currently on the market at this price range
http://www.amazon.com/...B000EOSHGQ
http://rover.ebay.com/...m270.l1313