I believe erc20 because many are already using that platform. ICO projects all use erc20 as a token platform that will be sold ico project. why you hesitate?
I hope you understand what these tokens are for, they are just like a gift card or coupons, it has no real value, I use to look at most of these ERC20 tokens and think that in coming months most of them would be 0 in value, unless the project have a real good use for them and a working platform I have no trust in them for now