I find hash has a less incapacitating buzz on me, i feel high and a nice body buzz, but I don't get that "trapped in my head" feeling that I love so much from the green... i guess it's a matter of taste. If you want a nice wake 'n' bake so you can go about your day pleasantly chill but not totally monged then a bit of hash is nice, but if you can't get a reliable source, I would skip it all together on our shores coz of the above mentioned nasties that sometimes get mixed in your smoke.
Peace