I was told that while siping does improve the handling in wet/snow/ice conditions, there is also a down side. The down side is if using the tires year round and you are on gravel/ sharp rock type roads, you are more prone to have chunks of tread cut from your tire. just something else to consider. Ken

 

Ken, I live back a mile from the pavement on a gravel road and while the stock treads pick up plenty of gravel I've never noticed any in the sipes nor any chunks missing.
Maybe my gravel is too big?

 

I have actually lost part of a lug on a tire from siping. It was from driving offroad with sharp rocks. This is a pretty specific case that 99% of people will never ever see. Large pieces of gravel are too big to jam in the sipes, only small stuff can do that and it seems unlikely that your tire will be damaged.

Unless you are trying to run the same tires for rock crawling on sharp rock and snow which isn't a good idea anyways, siping is very important for winter driving.