both are good, but now ico is still the main choice. maybe a few more years STO can be the best way to find new project funding. so we just wait ...
I personally chose STO because it was very good except that there are many rules that must be obeyed if you want to join
I think that sto is just a new term with a little difference from ico because it will give the investors the guarantee that they will get enough or fair gains with all their investments. Sto is also more secure as compared with ico but sto is just the new model of ico.
Check it here:
https://hackernoon.com/ico-or-sto-who-wins-fd43c3ee7b8d