Both have advantages and disadvantages, but if the project passed your criteria then buying in their pre sale has a huge advantage than buying in their ico, the biggest task is to check if the project is legit if it is legit then pre sale and ico is ok both options are profitable.
Exactly, there's always pros and cons between pre-sale and ICO. However pre-sale might be riskier than ICO since it's really hard to identify whether the project is legit or scam, but if it's not then you can get a lot of coins comparing to ICO phase.
i prefer to buy from ICO because it usually require small amount of contribution. If you participate on presale, you will need much contribution to be eligible.
Buy the tokens in ICO half, and buy half again once it hit exchange market.
This is another reason why some people didn't join pre-sale phase since it requires big capital to participate in. I personally choose ICO and if you believe that the project has a better future make sure to join in the beginning so you can get a cheaper price.