Worm drive vs. sidewinder for cementboard such as Hardiplank

Hi,

I am looking to buy my first circular saw and am trying to decide between the DWS535 worm drive and the DW364K sidewinder. The saw will only be used for DIY work around the house, including replacing a few Masonite siding boards with Hardiplank cement siding, for which I would buy an appropriate blade. I read the manuals on the DeWalt web site and for the DWS535 it says not to use with cement siding whereas for the DW364K it does not specifically state not to use it for such applications.

I have kind of been leaning towards the worm drive with its left hand side blade and I like the feel of worm drives better when I have tried them out in the store (although I have honestly never cut with a worm drive).

My question is, would anyone know why the worm drive would specifically state not to use with cement boards and if I were to only use it for a few replacement boards (i.e. not for use day in and day out putting up siding), could it really hurt the saw?

The only corded saw I ever use are worm drives. I do not know why they say not to use them with cement board, but personally I have many many many times, and have never had an issue. There is definitely a different feel to a worm drive vs. a side winder, but I prefer it. In my opinion, go worm drive, you will never look back.

Worm drives are great to cut with. Sidewinders tend to be a little lighter and

Thanks guys, I appreciate your input!