I've made, last year, both dry ice and dry sift, starting from excellent and rich trim. My results and opinion are:
Dry ice hash is less sticky, less potent, less flavoured than dry sift. I don't know news about safeness of smoking dry ice hash (it's only trim and CO², how could they harm?) but to me the resin obtained in this way is less enjoyable than dry sift hash, dry sift has a richer spectrum of flavours. Last but not less important is that because of process dry ice extraction too much green matter pollute resin.
This year I'll make only 120 microns dry sift hash in the Morrocan way 😏
Check my Special Kush diary and see my hash.