Sigma 17-70 IS

Hi all, I have recently picked up a Sigma 17-70 f2.8-f4 for a good price. I was wondering if anyone out there with the same lens has thoughts on the IS system. Do you use the one on the camera or the one on the lens or do you just leave both on?
I have tried all three settings and see very little difference, but just maybe slightly sharper with the lens IS rather than the camera body IS.
Would leaving both on create a negative reaction? It doesn't seem to make any difference as far as I can tell.
Any thoughts?

Harry

My Sigma 70-200mm f2.8 and 50-500mm both have OS but I tend to switch it off and use inbody SR as I get better results. Saying that I know a number of people on here that say the opposite but the general consensus is that you don't use both together (although I have at times, by mistake, and it didn't seem to make any difference).

Using the lens OS does result in a more stable viewfinder though ... but then it also seems to drain the camera battery faster.

Always switched off for me

I bought a 17-70 recently and did a wee test with lens and camera (k10D) "OS" just to see which if any was better,
I did this in a room lit by flourescent tubes and hand held without flash, all very scientific I know. The result was lens OS was sharper than the camera OS which was sharper than no OS at all.
Im not sure if the lens OS uses more battery power than the camera OS coz im still on my first charge since getting the lens.
happy testing
regards
stewart

Thanks for the input guys, my testing has followed pretty much the same pattern as stewcoo's, very scientific, and I agree that the lens OS seems to do a slightly better job and having both on doesn't affect it.
I will do some more testing later and see how it goes.

Harry